The whole instance basically exists because I wanted a way of accessing lemmy communities back when lemmy was barely a thing. I’ve been active for a while now, and it just so happens that 6000 of my closest friends have joined the instance since then :P
As for other communities, the only other one I use is !transgender. There are more out there, lots of them memey, like egg_irl etc, but I’ve never really been part of those spaces.