[KamenRanger1997]

These aren't entirely new Sentai, but are new rangers to add to Zenkaiger

First, a trio of one human and two kikainoids.

Jetkaiser
"Choujin Power"
Sentais: Jetman, Timeranger, Kyuranger
Numbers: 15, 24, 41
Colour: Green
Transformation Device: Geartlinger Mk2
Extra Forms: Time, Kyuren

His suit is basically a green version of Red Hawk with helmet and shoulder pads based on Jet Icarus (his colour is also a reference to the manga exclusive Sixth Ranger, "Green Eagle", which ties into the Sixth Ranger theming of the next two Zenkaigers). The "Geartlinger Mk2" is just a green Geartlinger. His Extra Forms are based on other Sentai with flying Mecha and have a space and time theming.

Zenkai Gobun
"Tokumei Power"
Sentai: Go-Busters
Number: 36
Colour: Silver
Transformation Device: Geartlinger Mk2
Weapons: Gobu Horn and Gobu Pincer
Mecha Form: Gobu Beet
Gattai: Zenkaioh TokkyuGobun

Zenkai Tokkyune
"Ressha Power"
Sentai: ToQger
Number: 38
Colour: Orange
Transformation Device: Geartlinger Mk2
Weapons: Tokkyune Light
Mecha Form: Tokkyune Train
Gattai: Zenkaioh TokkyuGobun

Next, I imagined Red Kaiser returning with his own team of kikainoids with the same colours and themes as the Zenkaigers

Zenkai Ryuson
"Kishiryu Power"
Sentai: Kishiryu Sentai Ryusoulger
Number: 43
Colour: Red (He and Red Kaiser fight over who's the true Red Ranger of their team)
Transformation Device: Geartlinger
Weapons: Ryuson Sword
Mecha Form: Ryuson Rex
Gattai: Zenkaioh RyusoGin

Zenkai Gingan
"Seijuu Power"
Sentai: Seijuu Sentai Gingaman
Number: 22
Colour: Yellow
Transformation Device: Geartlinger
Weapon: Gingan Claw
Mecha Form: Gingan Leon
Gattai: Zenkaioh RyusoGin

Zenkai Gosein
"Tensou Power"
Sentai: Tensou Sentai Goseiger
Number: 34
Colour: Pink
Transformation Device: Geartlinger
Weapons: Gosein Reader
Mecha Form: Gosein Dragon
Gattai: Zenkaioh Kiragosei

Zenkai Kiram
"Mashin Power"
Sentai: Mashin Sentai Kiramager
Number: 44
Colour: Blue
Transformation Device: Geartlinger
Weapons: Kiram Jetter (a sword shaped like Mashin Jetter)
Mecha Form: Kiram Fire
Gattai: Zenkaioh Kiragosei