Jackoamon

https://help.kagi.com/kagi/search-details/search-sources.html

They use many sources, including other search engines and specific websites, but also claim to use two of their own indexes.

Can’t say much in regards to perplexity, but I find kagi’s index to be quite nice. Especially if you find fortune forum posts helpful (which I do as a software dev). It’s paid only, so there’s no advertising incentive to the company and also a ton of configuration. I search a lot, so I went with the 10 dollar plan. 5 bucks gets you 300 searches a month, 10 is unlimited plus access to their LLM which documents information sources like perplexity.

Personally, I found perplexity to be quite annoying with the more ai focused UI and trying to learn your interests. Kagi is a search engine first plus some other features they’re developing.