There's so much perversion potential in that....

Insects and arachnids. Because appearntly that's been one of the rumored ones for the longest time next to pirates, and I think bugs are awesome. That and we'd have Bugmens in Super Sentai :lol.

Not to a little kid, and imagine how much candy Bandai would sell :lol

I'd like to see a Sentai team that works as a military unit again - like Changeman or Ohranger. It's an interesting approach to a Sentai team that we haven't seen for a long time.

- ESPer sentai that homages X-men, Teen Titans, and 21 Jump st. to an extent where they go undercover in a school suspected of being a front for an evil ESP group
- Like what ZeoRangerV said, Cowboy sentai would be good. Say they are space bounty hunters who come to earth to hunt down outlaws. And yes, they will be street vendors that sell burgers who secretly fight crime while leaving their clueless part-time worker to do the rest during fights.
- Medical-themed sentai where they use hi-tech medical gear to fight "evil" overgrown viruses
- Medieval sentai based off heraldic creatures(the animals on coat of arms)

I want to see the return of an evil Sentai team, like the NejiRangers (from Megaranger). They could be based on the negative traits of humanity (not sins, but personality traits)
Red = Anger / Hatred
Green = Greed (must have all the things)
Violet = Ambition (must win at all costs)
Pink = Pleasure
Yellow = Pain (live to enjoy the suffering of others)

I was thinking something like that but slightly different:

Red - Boxing
Blue - Lucha Libre wrestling
Yellow - Shaolin Kung-Fu
Black - Kendo
White - Taekwondo

Green - MMA

They've already done it a couple times with vehicles, but it'd be nice to see animal mecha that have their own robot modes. And then also combine. Or do like they did with the Time Force Megazord and have two distinct megazord modes. Just something different. Maybe even a return to a Shogun Megazord type design. With five humanoid mechs that become one larger one.

Yes please, and thank you. Psycho Rangers for the win!

Just give me a Western/cowboy-themed Sentai and I'm set.