These aren't what I would call 'best,' just supplemental when the best isn't cutting it.

Marginalia is pretty decent. I like that it lets you specifically search forums, wikis, blogs, or academia.

https://wiby.me/ is good for exploring old-school sites. This is more of an answer to "how do I 'surf the web' in 2026?" than what you're probably asking for. (The search itself is very keyword-y with no attempt to guess at relevance.)