[AkibaSilver]

One of the things I liked about Zi-O was its willingness to bring back some of the scondary riders. Nitoh, Aqua, the Hoppers, Yuutp, it's great to see more than just the main heroes come back for the big reunion movies. Yeah, I *know* it's a costcutting measure in the most part, but I still enjoy it!

But if we're gonna do series by series (that I've seen):
Blade - Tachibana. How can one man screw up the last 15 years? I wish to know.
Den-O - I'm always up for more Imagin
Decade - Honestly Tsukasa'll probably be back before too long.
OOO - Aqua again but not getting his ass kicked pls
Wizard - Haruto, Nitoh, Mayu, any of the mages would be good
Gaim - Well, we got Jonouchi back recently, Takatora got his own stage play... I'm gonna say Fifteen. Would be a surprise.
Drive - The entire Special Ops squad.
Ghost - Makoto and Kanon team up
Ex-Aid - Hiiro's Dad
Build - Legit any of them. Problem is, Sentou and Banjou don't quite feel right without the other, and the potato farmer and moustache man also bring their best as a team. Lesson of the day is, bring back Evol and have him cause more chaos.
Zi-O - Sougo randomly showing up and bodging a Ridewatch from the new guy's powers would be amusing. Espcially with as little context as possible. First sign of him is a loud "IWAE!"
Zero-One - Given Fuwa at the end of the series is going around trying to rescue people, he's incredibly easy to slot into an anniversary show. Plus, he's a lot less polarising than Aruto, which, ya know, is nice for the side of not having discourse.