When talking about public domain/creative commons characters I feel like people don't mention literally (almost) every single piece of SCP Foundation media, which is on a creative commons share-alike license. You have to also make your work that includes SCP stuff have the same license, which is probably why there are a lot of "SCP-like" games that don't actually use the setting like Control, Lobotomy Corporation, and Lethal Company that they made to have full control over their copyright. And you can't use stuff 173's original copyrighted design or the infinite IKEA being... an IKEA and not a parody. But it's still such a massive thing and I think that's it's really cool that something like it is free to use (and technically make money off of) for everyone.