Didn’t actually realise that the #StarTrek subreddits of /r/StarTrek & /r/DaystromInstitute had a #Lemmy community @ https://lemmy.world/c/startrek@startrek.website @startrek.

Given Trek fandom are often the first colonizers of online spaces in internet history (eg newsgroups) losing major Star Trek communities is big L for Reddit.

EDIT: Not permamently locked subreddits, got that wrong I think!