I mean, you can go to Itch’s browse tab and search top rated / top sellers if that’s your success metric.
Happily, I’d say there’s a diversity of genres and areas of focus there.
Cynically, if I were to appeal to the lowest common denominator, we’ve got a range of choices there:
Romantic sims, something friendily/charmingly horny, hot/cute anime guys/gals, short-form easy-to-play easy-to-understand simple-control browser shooters with fast restart rates, cute cartoon/animal/undead characters/settings, first person short horror (liminal space or monster jumpscares), emotional non-voice acted(so streamers can read the text with their own flavour) pixel art short adventure games that seem emotionally profound but aren’t that really, naratives that focus on depression and break ups in the rain, something that seems politically and philosophically profound but isn’t really, deckbuilding roguelikes, a short game that’s based around a funny easy to understand concept like a king on a throne that has to stop shitting himself or something. LOL I mean I sound like I’m bitterly judging these but I’ve played/watched all of them and they’re all great! lol Off for some more : D