I personally use SearX as my primary search engine (one local instance, the default searx.be instance as a fallback). Sometimes, I use one of the following search engines as well, but generally, there is no need for them in my case (for some of them, I retrieve their results with my SearX search, anyway). I rarely get to the point where SearX cannot provide the required and satisfactory results and I have to search with some specific search engine. The search engines I currently have set up in all of my browsers on both desktops and mobile phones are:

• SearX,
• DuckDuckGo,
• StartPage,
• Qwant,
• Metager and
• some specific search shortcuts for a few websites (Wikipedia, Lemmy, ...).

I have one Whoogle instance set up too, just for testing purposes, though. And I love the idea of per website aggregated results provided by Gigablast, but Gigablast is way too slow to use regularly. Interesting idea, though.