I've read most of this page and am surprised that nobody has (either positively or negatively) mentioned fandom.com, a wiki-farm founded over 20 years ago by one of Wikipedia's founders and another Wikipedia enthusiast. Formerly "Wikicities" then "Wikia", now "Fandom". Hosts about a third of a million communities. Supported by ads at top and side of pages, but logged-in users see very little advertising. Very secure, rarely exploited by malicious bots or other hackers. Numerically dominated by game, TV, and film sites, but many non-entertainment communities as well. The biggest English-languages sites are listed at https://community.fandom.com/wiki/Hub:Big_wikis but numerous other languages are included.

While I agree it’s a good resource, please note there’s quite a few controversies[1] with the site, e.g. “The excessive monetization model of user-generated content has been criticized by several newspaper outlets, such as the British newspaper The Guardian”

[1] https://en.wikipedia.org/wiki/Fandom_(website)

It's a great hub, and it's quite easy to fall down a rabbithole there!