Well first off, I'm gonna miss my favorite nerdy subreddits.
r/wow, r/Morrowind, r/Oblivion, r/Skyrim, r/Elderscrolls, and even r/trueSTL. Happy that Skyrimmods is here though!
Aside from that though, r/botchedsurgeries, r/amitheasshole, and r/hobbydrama.
The rest would be various animal subs, but hopefully, they find new homes quickly.