Do you intend to focus on anime and manga exclusively (which is general discussion) or by your title "all fiction" (which is off-topic for threads non anime/manga |or} covers both anime/manga in addition to other media)
Eva01, well, not finished it. But somehow watch the last episode (which confuse me since i dont know what the full context is). My fave Kamen Rider by design are OOO's Tajadol, Ghost's Ore Damashi, and Den-O Liner form though
FabGlass What the- Why would you watch the last episode just like that?
Well, so far, my favorite Heisei Rider designs are Ultimate Kuuga, Another Agito, and Zangetsu. Favorite Showa Rider designs are Black, Shadow Moon, Amazon, and Super-1 (YES, THE TASSELS ARE A PLUS; FIGHT ME).
Well, since you don't seem new to the Kamen Rider franchise, I do recommend Gaim, but keep in mind that the first 14 episodes or so are quite silly and comedic, and the show doesn't drop the bullshit and gets good until episode 20, so it requires patience to get to the good part. Gaim is basically the Gundam ZZ of KR.
Agito is another recommendation, it has what is easily, in my opinion, the best Kamen Rider antagonist ever, along with a good story.