>>23574423
Firstly, understand that with some relatively meaningless exceptions, all Riders are entirely standalone stories that do not meaningfully build off of previous shows. In the Showa era, there would be occasional guest appearances of past riders every so often but the series are still very much able to be enjoyed separately. Ignore the anniversary shows Decade and Zi-O
Are you comfortable with Showa-era cheese and older, more formulaic shows? Then the original is a great place to start. (If you're allergic to old stuff but still want to learn more about the OG, the recent Shin Kamen Rider movie by Hideaki Anno is a great, loving tribute to the original)
Do you like J-Drama, 2000's Japan and slasher movies? Check out Kuuga, the series that revived the franchise for the Heisei era.
Do you like detective stories, and more toyetic/anime like action? W is the first of the "second wave" of Heisei series that established a lot of the current common tropes and formulas that the series still uses today.
Do you want to hop in to an ongoing show and watch along with a community? Zeztz was designed from the ground-up to be a great "baby's first Rider" and even more to the point, "The West's first Rider". Has been off to a pretty good start so far, and is very easy to catch up and follow along with thanks to Toei finally putting an officially translated version of the show out for an international audience as-it-airs.
These are just a handful of particularly strong "Start Here" shows. Not necessarily the best the franchise has to offer, but good and worth checking out if any of them particularly strike your fancy. By and large you probably can just look at the design language of a main rider and get a sense if you'd be interested in watching their show. Don't worry too much about side material off the top.
