It doesn't index more stuff overall, but marginalia.nu has a pretty great system for identifying non-commercial sites, which tend to be higher quality since they're not trying to sell crap.

The creator recently started working on it full-time.

https://search.marginalia.nu/

Precisely what I wanted to ask as well. I only of yandex which gives really good results like old google, but I'd rather have alternatives in case when yandex fails.

The general search engines that I know of are (ordered from best to worst): - yandex - ddg - google

Literally any search engine, regardless of affiliation, is welcome as long as it returns google-grade results (old google ofc) for more than half its searches.