Kagi search is a paid search engine that delivers higher quality results with no ads. I'm currently using the free trial (you get 100 searches for free) and enjoying it.
This is something Google can't and won't do because they, and the people they depend on, would lose too much ad revenue. This is going to be a future problem as we transition to AI and AI assisted search for information retrieval.
They also have their (two) own indexes.
Tbh, for me (as small town dev) it feels like magic how fast those different sources are combined, additionally with user search preferences like raising or blocking certain domains. Insides welcome :)
Edit: Here [2] are some benchmarks and general strategies they pursue. Would love to read more details.
[1] https://help.kagi.com/kagi/search-details/search-sources.htm...
[2] https://help.kagi.com/kagi/search-details/search-speed.html