What are some good alternatives to Wikipedia and TV Tropes?

There really aren't any alternatives. At least nothing as all-encompassing as those two

I stand by that Wikipedia is truly the greatest site on the entire Internet, no real reason to create a competitor when you can download the entirety of it for free

I think the next step down from Wikipedia is an actual encyclopedia. Also news websites for archives.

What are your concerns with these sites?

Specifically what is your problem with those? You haven't really explained anywhere in the thread. It's kinda relevant for knowing what to recommend.

Best bet is probably a book.

Is there an issue with these sites I'm not aware of?

I don't know if it's good yet, but I think one of the Lemmy devs is trying to make a federated Wikipedia. I honestly don't see the need for it, but it's his time and if he wants to work on it, great. I wish him well.

AllTheTropes

archive.org is great for borrowing old books, that you probably can't get your hands on otherwise. Just need a bit of research following references to find titles to search for.

Everything2.org was a significant wikipedia competitor back in the early 00s. It's still up but I havent been there in a decade and a half. Could be worth your time, it was interesting to get lost in back in the Web 1.0 days