Kuuga - Worth watching for the character relationships. Not too heavy on plot.
Agito - Very plot heavy with a large cast. Can be intimidating for newcomers.
Ryuki - Lots of action with an easy to follow plot and likable characters.
Faiz - The story goes in a shitzillion directions, but it has really fleshed out relationships for all the characters. Story kind of falls apart torwards the end.
Blade - Bland character and the first half of the show is VERY dull, but it picks up greatly torwards the end.
Hibiki - The first 32 episodes are very underrated. Totally worth watching for its unique story and suit designs. Stop watching after 32. Trust me.
Kabuto - Strong premise with a large cast of characters that, ultimately, don’t end up doing anything. The story falls apart torwards the end, but I’d still reccomend it for the great secondary riders.
Kiva - Unique Dial-Timeline storytelling (could confuse new viewers) with great designs, soundtrack, and main characters. The plot doesn’t really go anywhere, and the ending is kind of a flat note.
Decade - Don’t watch Decade.
W - Great fights, characters, soundtrack, premise, and a story that has a perfect mix of filler and plot episodes.
OOO - Constantly changing story driven by character motivations. Manages to get you to feel sympathy for the villains too. Ska soundtrack is also a plus.
Fourze - VERY strong cast, but the plot doesn’t really go anywhere. However, the first 12 episodes are some of the best episodes in Kamen Rider History. Totally worth watching.
Wizard - Dull main character and slow-moving story, but has likable secondary characters and introduced a lot of neat concepts that were mostly not delivered on.