I’ve found a few groups on Meetup where folks are looking for games or looking for players for their tables locally. Other than that, related Discord communities are good for online games.
RPG
Discussion of table top roleplaying games.
I took my first stab at TTRPGing with new people online this past spring and got insanely lucky. I went to Roll20's LFG postings and found someone who wanted to run a Band of Blades campaign. Reading their sign-up doc, it was clear this person wanted to run a fun, respectful, and open table.
We all met up for Session 0, and the GM did a wonderful job of laying out his expectations for Lines and Veils. He made everyone comfortable about using safety tools and set everyone up for a fun roleplaying experience. All the players have been friendly and done a great job of sharing the spotlight and collaborating. Everyone has been on time and communicated when they were unable to make a session.
I've read many horror stories about online pickup games, so I'm shocked at how positive of an experience my first attempt has been. So I guess my recommendation would be: give Roll20 LFG a look!
Since I do not want to use discord I can only search in forums, on discord instances you are also always banned if you look for players there but then do not use them to play. Unfortunately, the forums die out or there is only searched for DnD :(
What is FLGS?
FLGS = Friendly local game store
I am an ancient member of a large online community. However, these last 5 years, I've been living in a city with a huge RPG club. So finding player isn't an issue at all.