If you're interested in writing (e.g. fiction/poetry) there's !writing_lounge@literature.cafe and !writing@slrpnk.net
If you're interested in fitness, !fitness@lemmy.world and !Weightroom@sh.itjust.works have a certain amount of "report how you're doing".
If you create a new community, be sure to announce it on !newcommunities@lemmy.world