There were a few professional psychology related subreddits that had moderation that verified licensure to allow posting only by actually professionals and that was pretty nice

There was also askatherapist which was interesting to get unfiltered client perspectives and offer clinician feedback

Morbidquestions was an interesting sub sometimes. 80% of the time it was stupid edgelord bullshit but sometimes someone would ask a really interesting dark question

Creepywikipedia was a good one and is explained by the name