I just had a somewhat silly idea, actually: loosely adapting (by which I mean just using the suits and mecha from) a pre-Zyuranger sentai into Power Rangers. I'm not sure how serious a suggestion this is, but if we went that route I'd suggest going with Jetman (birds/planes). The main problem I see with this idea is that it kind of limits what we could do, though. But again, I'm not sure how serious I am about this, so yeah.

Or conversely, one that hasn't been adapted yet, like Go-Busters (special ops/animals), the alternate Go-Busters, or Kyoryuger (DINOSAURS AND SAMBA!). But, um, yeah.