You probably have to find out what your hobbies and interests are and search / ask accordingly. And if you miss something, be the change you want to see and create new communities.

I personally avoid politics as much as possible, and found some great communities. Most prominently !lemmyshitpost@lemmy.world, !memes@lemmy.ml and !196@lemmy.blahaj.zone.

Edit: Oh. This wasn’t a question you asked, but rather a list of these communities, my bad. My advice still stands though.