I think a relationship that stands out to me is Philip, Shotarou, Akiko and Terui in Kamen Rider W - I really love the themes of found family the show has going on for them. (SO GOOD. And a lot of goofy antics I'd link but google is being uncooperative. Movies/extra material including the W cast always has so much going for them.) I tried to think of an OTP but I'm pretty neutral to most pairings...

Trick or treat! ♥