Marginalia Search is an AI-free[1] search engine, mostly because I don't think search is much helped by AI. The sorts of problems that does better than traditional IR-methods based search are things traditional search engines never did particularly well anyway.
https://search.marginalia.nu/ https://git.marginalia.nu/
[1] For whatever AI means these days. Given everything people claim to be AI in their marketing, there's an argument to be made all software is AI.