Theme/Motif:Animals/Detectives
Team Name: Detective Sentai Noiranger
Sai Red
Tora Orange
Unagi Blue
Kujaku Black
Snake Green
Panda Yellow
Condor Gold
Lion Silver
Rabbit Pink
Gorilla Violet

I wish we could make a reunion to share some ideas.

Theme/Motif:Time
Team Name: Jikan Sentai Mirairanger
MiraiRed
MiraiGreen
MiraiYellow
MiraiBlue
MiraiWhite
MiraiGold

jikan sentai miraiman would sound much more cool

Theme/Motif:Martial Arts
Team Name: Budo Sentai Yaseiger
Yasei Pegasus
Yasei Dragon
Yasei Griffiin
Yasei Chimera
Yasei Phoenix
Yasei Tiger

Theme/Motif:Fruits
Team Name:Fruit Sentai Eiyouger
EiyouRed
EiyouGreen
EiyouBlue
EiyouBlack
EiyouPink
EiyouSilver
EiyouYellow

Funny, I've had a concept in my head FOREVER involving time!
Time/Time Differences
Mamonaku Sentai Miraiger
Mirai Red - a modern-day woman who finds a pocket watch henshin device and ends up having to fight with rangers from other time periods throughout different points in time in order to stop the destruction of the space-time continuum. She's an average person who struggles at first with being the leader but grows into it.
Mirai Yellow - a caveman who finds a pocket watch henshin device and has to do the same. he enjoys the simple things in life, and uses brute strength to battle
Mirai Blue - a knight who finds a pocket watch henshin device and has to do the same. he is known for being very honorous and strict, which can have it's pros and cons
Mirai Green - a ninja who finds a pocket watch henshin device and has to do the same. he is very sneaky and is able to quickly use his wits to his advantage
Mirai Pink - a pharaoh who finds a pocket watch henshin device and has to do the same. he can be a bit arrogant at times but is usually able to redeem himself with his strong fighting prowess
Mirai Future - a member of the Time Protection Bureau (nod to Timeranger), who comes from the year 3050. Uses a digital smart-watch morpher, and arrives to assist the Rangers for initially selfish reasons. He buts heads with Mirai Red, as despite being from the future he carries that backward notion that women can't lead. Eventually realizes his place on the team and works to better himself with the help of the other Rangers
Saturn Ranger - a deity who uses the power of Saturn, and has the power of time control. He takes on the appearance of a teenage boy. He is part of a different sentai team that hasn't fully awoken yet, but formed this team to quickly deal with the issues at hand. Specifically sent the pocketwatch henshin devices to different time periods in the hopes that they would be found and used. Doesn't reveal himself until much later in the series.
Henshin Device:
Pocketwatcher - the general changer of the main team, which has the ability to both Morph and to transport it's user to whatever year they choose (up to to the present). There's also an auto-transport feature in case on team member is fighting a monster in a time period and automatically needs backup. It can summon mech and there's a placement to create mech out of objects.
Smartwatcher - the main changer of Mirai Future, with his changer being based on a digitial smart-watch (i.e. Apple Watch)
Weapons:
Mirai Blaster - Mirai Red's main weapon, a stylized blaster
Mirai Smasher - Mirai Yellow's main weapon, a stylized sledgehammer
Mirai Saber - Mirai Blue's main weapon, a stylized sword
Mirai Daggers - Mirai Green's main weapons, a set stylized kunai knives
Mirai Sceptor - Mirai Pink's main weapon, a stylized sceptor
Mirai Solar Shot - One of Mirai Future's two weapons, a stylized blaster
Mirai Solar Stab - One of Mirai Future's two weapons, a stylized sword
Mirai Saver - a blaster/sword that can be used by any of the team members to gain a 'super form'
Mirai Destroyer - a blaster/sword that can be used by any of the team members to gain an 'ultra form', which can be extremely dangerous and have the chance of making the user go berserk with dark energy
Saturn Sceptor - Saturn Ranger's highly stylized scepter/henshin device
Arsenal:
Mirai Saver Armor - the armor summoned with the Mirai Saver
Mirai Destroyer Growths - a monstrous set of armorous 'growths' coming out of the Ranger's suits when using the Mirai Destroyer
Mecha:
Mirai Jetter - Mirari Red's mech, a stylized jet
Mirai Tiger - Mirai Yellow's mech, a stylized saber-tooth-tiger
Mirai Horse - Mirai Blue's mech, a stylized horse
Mirai Panda - Mirai Green's mech, a stylized horse
Mirai Sphynx - Mirai Pink's mech, a stylized sphynx
Mirai Reviver - Mirai Future's mech, a stylized humanoid mech
Mirai Argo - An extra pirate ship mech that is used in tandem with the Mirai Saver
Mirai Wrath - An extra dragon mech that is used in tandem with the Mirai Destroyer
Combined Mecha:
Mirai Combiner - The combination of the five main mech, with different formations focusing on different aspects of the mech: Fly Formation, Smasher Formation, Knight Formation, Stealth Formation, Emporer Formation
Mirai Revive Combiner - A combination of the main five mech along with the Mirai Reviver. As it's assembled 'around' the Mirai Reviver, there is only the main formation
Mirai Argo Combiner - A combination of the main five mech along with the Mirai Argo. As it's assembled 'around' the Mirai Argo, there is only the main formation
Mirai Wrath Combiner - A combination of the main five mech along with the Mirai Wrath. As it's assembled 'around' the Mirai Wrath, there is only the main formation
Mirai Oblivion - A combination of the Mirai Argo and the Mirai Wrath, with two formations: Ship Formation & Dragon Formation
Mirai Ultra Combiner - A combination of all of the mech. Due to the complexity of the combination, there is only one formation
Villians:
TBA

Theme/Motif:Espionage/technology/extreme sports/shapes/vehicles/military/special ops/military hardware/military science/martial arts/military sports/military weaponry./animals.
Team Name:tokumu sentai X-Sol

Theme/Motif:Card/Insects
Team Name: Toranpu Sentai Konchuuger
Red Dragonfly
Black Mantis
Blue Locust
Pink Hornet
Yellow Moth
Green Cicada

My sentai team theme and motif will be animals/heraldry/nature/space/medieval/elementals/shapes/knights/constellations.

Theme/Motif:Knights
Team Name:Bitoku Sentai Naitoger
NaitoRed
NaitoGreen
NaitoBlue
NaitoYellow
NaitoWhite
Naito Soldier

Theme/Motif:technology/universal forces
kikai sentai cyberman
CyberRed
CyberGreen
CyberBlue
CyberYellow
CyberPink
CyberSilver

Theme/Motif:Angels
Team Name:Angel Sentai Haloranger
AngelRed
AngelGreen
AngelWhite
AngelBlue
AngelPink
AngelGold
AngelBlack
AngelYellow

Goseiger already used that.

Theme/Motif:Oni
Team Name:Onigaku Sentai Akumaranger
Akuma Red
Akuma Blue
Akuma Yellow
Akuma Green
Akuma Silver
Akuma Gold

Theme/Motif:Technology
Team Name:Network Sentai Dataranger
Data 1
Data 2
Data 3
Data 4
Data 5
Data 6

Theme/Motif:Sealife
Team Name:Suisei Sentai Keitouger
Red Same
Blue Kujira
Violet Iruka
Green Shachi
Pink Unagi
Gold Kingyo

The nitro machines design will have resemblance from the hot wheels vehicles.

So.....Shift Cars from Kamen Rider Drive then ?

Saiko sentai valorman will be a sequel to Braveman.

Theme/Motif:Ninjas
Team Name:Shinobi Sentai Ninranger
Shinobi Red
Shinobi Blue
Shinobi Green
Shinobi Yellow
Shinobi Pink
Shinobi Master

Theme/Motif:Sports/animals
Team name:Yõki sentai sportman
Red Baseball-Falcon
Green football-Rhino
Black basket-Bull
Yellow Soccer-Lion
Blue Swimmer-Dolphin
White Volley-Tiger
Orange Lacrosse-Horse

Theme/Motif: Space Western/Vs Team

Team Name: Bengoshi Sentai Navahoger Vs Sabishi Sentai Korutoman (Lawmen Squadron Navajo-Ranger) Vs (Lonesome Squadron Colt-Man)

Rangers:Lawmen
Navaho Red Sensaki (M) - A former criminal who cause trouble to survive but was offered to join the force by the chief because of his exceptional skill, Red is a little stubborn always prefer to ignore his superior and laidback whenever he want but mostly follow his order

Side Weapon : Cassidy - A Remington revolver with a word "Cassidy" engraved on it's barrel that he got from a dead outlaw during his criminal life

Navaho Blue Takabasa (M) - The only Avian (bird people) and non-human lawman in recent year who join the force in purpose to break barrier between human and non-human, he always cover his face because of his insecurity as a "non-human"

Side Weapon : Totem Dagger - Just like the name implies, it's a dagger with a carved totem as a handle and Blue use it in close combat......even in a gunfight

Navaho White Nonosei (F) - A detective recently signed to join the division to investigate cases about outlaws aide by unknown source

Side Weapon : Cuff Knuckle - A special type of handcuffs that combine into a brass knuckle

Rangers:Bounty Hunters
Red Colt Hiru Daruma (M) - A notorious outlaw and one half of the Daruma Brothers alongside with his brother Bud, after his brother K.I.A. he become a bounty hunter and set out to find his brother's lost gun Cassidy

Violet Colt Jaaku "Jack" Murasaki (M) - A lawman from a special force Beauregard who was frame for murder of a captain, so he hide away and become a bounty hunter to set out finding the guy who frame him. Being a former lawman he's skilled in all firearms especially rifle to the point he was given the name "The Rifleman" for being the best rifle gunman of recent years.

Pink Colt Yukina Mohaya (F) - A woman who were caught by bandits turn into slave, but was saved by a lawman who eventually became her husband. After her husband was killed by an unknown assassin she become a bounty hunter to live and search for the killer

Morpher/Changer/Henshin Device:
Piece Maker - 1911 pistol that reload ammo using C-Gillian to scan the gun but when insert their badge they henshin
Sundance - A custom made Piece Maker build in Red Colt own Colt Lighting revolver but he can only use normal Gillian currency to reload
The Kid - A custom made Piece Maker build in Violet sawed off Spencer Rifle with attachable long barrel and scope but it fire twice the bullet so it take more Gillian then usual
Miss Holiday - A custom made Piece Maker build in Pink Derringer pistol but it only contain 2 bullet making it the most powerful pistol when fire in close-range

Weapons/Arsenal:
Python Bazooka - Finisher Cannon

Mecha/Zords: Single Action Army or S.A.A.
Smiths & Wesson - Twin Jet
Rhino - Tank
Navy - Submarine
Dragoon - Harley Bike

Combined Mecha/Megazords:
Allies:
Jingle (Extra Hero) -

Main Weapon : The Atonement

Sorry I had to make more

Villians:
Ceaser Cachino - A rich entrepreneur who had a shady business by paying bandits, thugs & criminals to do all his dirty work.

Zamoru (The Mole)

Hachi - A gang leader who do things by his own rule & completely disregard anyone around him including his own gang members that he considered incompetent, while Hachi isn't his real name he did got by being infamous for killing his enemies with his hatchet.

Monsters:

Theme/Motif:insect/scientists/nature
Team Name:Juukou Sentai Mushiman
Mushi Red-fire/beetle
Mushi Green-Wood/Forest/Praying mantis
Mushi Blue-Water/Dragonfly
Mushi Yellow-Earth/Ant
Mushi Pink-Wind/Butterfly
Mushi Silver-Metal/Atlas beetle

This might be too dark, but...

Theme/Motif: Ghosts
Team name: Mienai Sentai Yureiger (Invisible Sentai Ghost-ger)
Yurei Fire
Yurei Drown
Yurei Sick
Yurei Crash
Yurei Lost
Yurei Yaiba

The rangers are literally ghosts (their ranger names allude to their causes of death) who are recruited by a medium to fight some kind of ghostly evil, except for Yurei Yaiba, who is the medium's apprentice channeling the ghost of a long-dead samurai. The monsters are possessed objects, with the high-ranked villains based on traditional tsukumogami. The red ranger's powerup is Angel Yurei Fire, which he obtains by saving the life of someone who was about to become the seventh Yureiger and getting the powers that were supposed to go to them. Oh, and their mecha are based on everyday vehicles, which they actually were before the Yureigers possessed them.

Theme/Motif: knights/heraldry/animals/nature/space/shapes/medieval/magitek/coat of arms
Team name: Primal task force Magnaman
Magna Red
Magna Green
Magna Blue
Magna Yellow
Magna Pink
Magna white

Theme/Motif: Motorcycles
Team name: Kōsoku Sentai Bikeranger (High Speed Team Bike-ranger)

Our hearts are engines at full throttle!
Biker Blue, ready!
Biker Pink, set!
Bikers Black & White, on your mark!
Biker Red, GO!
Kōsoku Sentai Bikeranger! (said while running towards the enemy)

Red, Blue and Pink are the core team with their three motorcycle mecha combining into BikeKing Robo. Black & White start out as rivals before joining them, their shared mecha is a motorcycle and sidecar that transforms into BrakeKing Bot. All together, they can combine into either Riding BikeKing Robo (bike-and-rider formation) or Great BikeKing Robot (larger humanoid formation).

Takara Sentai Umiraider (treasure crew sea-raider)

The core team:
Fierce hunter, Shark Raider!
Bold fencer, Swordfish Raider!
Swift dancer, Dolphin Raider!

The two add-ons:
Clever trickster, Octopus Raider!
Sturdy traveler, Turtle Raider!

The sixth:
Ice-cold warrior, Orca Raider!

It's set in a future where ships and sea travel have entered a second golden age, and with them, piracy. A brilliant scientist creates the five Swash Bucklers for five chosen heroes who are supposed to become the Umirangers. Unfortunately pirates attack the ship the Bucklers are being transported on, stealing four of the five, one of which gets damaged. After accidentally locking the Bucklers to themselves, the pirates have to step up and save the world from the evil Atlantian empire!

The three intact stolen Swash Bucklers are used by Red, Blue and Pink, the pirates' captain, cook/swordsman and navigator. Their doctor studies the damaged one and eventually manages to repair it and reverse-engineer another for the gunner, and they become Yellow and Green. Meanwhile, Black is one of the five who were originally chosen to become Umirangers and the only one who kept his Swash Buckler, and he hunts the Umiraiders at first before realizing they're more heroic than the navy he served and joining them.

Red's power-up form is the Fearless Commander, WhaleShark Raider!

Their combined mecha is called UmiCaptain, formed from the Shark, Swordfish and Dolphin mecha, and the Octopus and Turtle mecha can add on to arm it with a whip (Octopus), axe (Turtle) or anchor (both). The Black ranger has his own mecha, UmiBravo, formed from his Orca mecha and an unmanned Manta ray. There's also a sentient Whale that can transform on its own into UmiViking, or combine with all seven of the others into UmiAdmiral.

(Basically, I'm salty that Gokaiger wasted the amazing idea of pirate sentai on an anniversary crossover.)

Two things:

1) Give us the goddamn dragon themed Sentai dangit.

2) Horror theme similar to Kiva.

Agreed! Here's what I'd do with those (just my personal take):

1) Gozen Sentai Dragoger ("gozen" means "roaring")
Roaring fire dragon, DragoRed!
Crashing sea serpent, DragoBlue!
Howling sky wyvern, DragoGreen!
Rumbling land wyrm, DragoYellow!
Booming thunder drake, DragoPink!
Shining light gryphon, DragoSlayer!

2) Kowai Sentai Monstranger ("kowai" means "scary" and "Monstranger" is both a combination of "monster" and "ranger" and a play on "strange")
Vampire Red!
Mummy Yellow!
Franken Pink!
Werewolf Blue!
Mermaid Green!
And their pre-battle catchphrase would be Red telling the MOTW "We'll show you how real monsters [insert activity relevant to the episode]!"

Maybe slightly off-topic,but I wonder whether they will do something like Gokaiger next year or whether they'll save it for the 50th anniversary.

Theme/Motif: Highschool Delinquent/Street Gangs

When a world fill with chaos full of gang members and people with the ability to turn into monsters, there are outcast who would fight for peace calling themselves "Tsuiyuusha" but they're slowly fade away due to their status by the authorities and society. However there are some who still fight on in secret especially in a form of Special Operative Line-up Enforcers or S.O.L.E. consist of new generation of misfits called

Team Name: Choujiyu Sentai Hanranger (Super Freedom Squadron Rebellion-Ranger)

Rangers:
Hanran Green Kyochiro "Kyo" Narasu (M) - Former delinquent who join the force simply because his sister want him to stay out of trouble, being the most experience making him the leader of the team and even given the name Leash Man due to his "old reputation" and changes after joining the force which is why he is consider a traitor by other delinquents. He's the only Hanranger who transform in plain sight except the others because they worried people wouldn't accept a bunch of delinquents being the protector

Hanran Red Reina "Asuka" Yasei (F) - Former member of the Blue Flame Gang, she left and the gang were disband after their leader had an association with a group who responsible for the monster attack. Despite being part of the team she most of the time fight the enemies head-on her own since she was the toughest fighter from her "former gang". Originally just an innocent girl who want violent to stop she realize using words it's not enough to stop it after her friend died in a gang violence.

Hanran Yellow Joichi "Joe" Heikin (M) - Initially just a typical highschooler he was eventually chosen to become a Hanranger after surviving a gang violence, although was never a trouble maker he always get caught in a crossfire and sometime unintentionally like to intervene whenever trouble occur

Hanran Blue Saki Shizukana (F) - A quite, rich but a strong highschool girl, she use her family money to be a trained fighter while her parents are mostly overseas. Her family fortune makes her an easy target but being able to hold on her own also makes her a popular student and even refer to as Saki-sama (Mistress Saki)

Hanran Black Kanae Tsudaru (M) - A somewhat mysterious person other then being known as The Brutist (despite barely looking like a big hulking man) by the public eye, he was chosen to be a Hanranger out of sheer desperation of seeking the 5th member. His fighting prowess is on par with Green and sometimes act a bit of a jerk toward the team

Morpher/Changer/Henshin Device:

Weapons/Arsenal:
Free Lancer
Beater
E.G. Launcher

Mecha/Zords:

Combined Mecha/Megazords:

Allies:

Sorry I had to make more

Villians:
Fleur Kimura (F) - A quite blue haired young woman carrying a porcelain doll named Francais wherever she go.

Kurata Kimura

Ryoshi Yamazaki

Monsters:

Are you make this sentai based on 21 jump street ?

Wow, that's a really cool and original idea!

I'd love to see more sentai like the Lupinrangers who, while still firmly on the side of good, aren't the squeaky-clean heroes most teams are.

Most of it based on a Toku show called Wild 7 (1972) and Sukeban Deka (1985).....and it's several copycats

Theme: "creepy" animals, technology
Kaijin Sentai Cyborger

Information web, Cybor Spider!
Echoing signal, Cybor Bat!
Electric buzzing, Cybor Wasp!
Powerful coil, Cybor Cobra!
Deepest search, Cybor Mole!

The joke is that they're all based on historic monsters in Kamen Rider (the first two monsters were spider and bat themed, the first female monster was bee themed, the first to be upgraded was cobra themed, and the first to turn good was mole themed).

This is a weird theme for a sentai, but hear me out: Love.
Aisuru Sentai HeartRanger

Protecting all I can! I love my friends! Red Heart! / Protecting all the world! I love everyone! Red Heart of Gold!
Honoring our family! I love my father! Blue Heart!
Brightening the future! I love my daughter! Pink Heart!
Carrying your dream! I love my brother! Green Heart!
Becoming a hero! I love my idol! Yellow Heart!
Fighting hand in hand! We love each other! Black Heart and White Heart!
Breaking people's bonds! I love no one! Steel Heart! / Breaking evil's hold! I love myself! Silver Heart!

They could have vehicular combat mechas ?