So, whenever this comes up, I can't help but promote an interesting project - Mwmbl. They really can't replace a search engine at the moment, but their ambition is rather audacious - to basically do to publicly available information and the ability to search it, what Wikipedia has done with encyclopaedic knowledge, focusing on making it available for free, without ads, with user curation on top of an algorithm and the end goal of making searching the internet a public good.

I've been using it as my "first search" search engine, helping to curate results if possible, and then switching to a different one if there were no good results. (As I said: Not close to a replacement for the functionality of a search engine just yet). I also have their Firefox add-on helping indexing, and the web crawler CLI script is running on my server - to highlight two more things that are not very intrusive and help them out. Anyone that is interested, check them out here: https://book.mwmbl.org/ - the main place to connect would be on their matrix, if you are interested to learn even more.