I’ve seen this mentioned a few times already: people wondering why certain communities don’t show up in their instance. You need to first search for that community via the magnifying glass icon and type in “[email protected]”
Notice the exclamation mark at the beginning. Might take a few seconds. This will teach your instance about the remote community.
As someone who only signed up to Lemmy yesterday, I have no idea what communities aren’t showing up because well… They aren’t showing up 🤷
The new lemmy version actually makes this post irrelevant. If you want to discover new communities go to https://lemmyverse.net/communities click on the Home icon at the top right, type in ‘waveform.social’ and then open any communities you’re interested in.