Depends on what you're into. The not so big meme ones are great for casual amusement. In fact any community that isn't the biggest on Lemmy is generally good.
That's generally how I found Reddit to be. Avoid the largest communities and find some with a decent amount of activity.
The trick is that besides tech, memes, news and politics, there isn't really that big of other communities.
!newcommunities@lemmy.world
!trendingcommunities@feddit.nl