Gregory's Server@andybaio Ah! This is it! YaCy: https://yacy.net
You'll need to curate the list yourself, but the softer for crawling and searching is packed easily enough to try out. I've tried it locally before. Bit of a faff to maintain the site curation. I seem to remember taking a whole evening and maybe a sleep to get my head around the UI.
@andybaio I just tried the Docker version. It defaults to a peer-to-peer index i.e. it's currently pulling in others' indexes. I don't know the validity of that index but looking at the search results page, there's a Peer-to-Peer/Privacy toggle for the results, which lets you keep your searches to an index of your own. I've totally forgotten how to set up a private index though.