I used to run a bot that searched for and posted about abandoned subreddits (subreddits without mods, or where the only mod was the admin-run "request_bot"). My database of abandoned (and banned) subreddits is about 1 million subreddits. I stopped posting the data to Reddit as part of the API protests. I was releasing about 100 randomly selected subreddits from the database a day.
I don't think I'm going to start releasing the data back on Reddit again, at least not for the forseeable future. Should I release it on Lemmy instead?
My database is uncensored, there's no feasable way to check 1M subreddits by hand, so it includes a lot of subreddit that are porn related.