Hibiki probably would have better advice on this or NotIgor for that matter but the series I started with personally was Ex-Aid. It's probably one of the easier themes for someone unfamiliar to Kamen Rider to adapt to since the transformations are based on different genres of video games. As far as other seasons go I'm not too sure as I've only seen a few others such as Den-O, a bit of OOO and W, and Fourze. Most of what I've seen I've enjoyed but I also have been avoiding the seasons others tell me are less than great.

Due to not having any Western license, there's no legal streaming for Kamen Rider (and as such I'll refrain from directly pointing to any site). However you can find many fansub groups with simple searches. Where you begin is almost entirely up to you, as just about every season is independent from one another save for similar concepts. I would recommend... Kuuga, as it was the beginning of the heisei era of the series, but can be a slog. W, considered one of the best, if not the best, for a variety of reasons. It's one of the easiest to get into and is generally appreciated by long time fans and newbies. OOO, it's my favorite. Ex-Aid, another season very easy to get into, and probably the most well loved on the Phansite after I accidently let it spread like a fire for a bit... Then intentionally let the fire spread. Build, this season is the most recent and is still airing, but is arguably shaping up to being one of the strongest written seasons already.

Fourze- Likeable characters( except JK who is actually hitler) Unlikeable villains Space Friendship HWATCHA What’s not to love?