I am especially interested in trying to help family / etc. who are not very sophisticated in their browsing habits be able to check themselves at least, with some kind of external measure of whether a website is reasonable or not. For example, based on the links / associations / authors / circles that some video or news site has, is this likely to be an objective source of info, or down a hole of extremism?
I would be really interested if someone has come across this.
I'd wager money that there's a bigger issue here than individual videos themselves; you can take down one video but you're not stopping the slow tide that converts people.
For US audiences and fact-checkers, RAND maintains a comprehensive catalog of lists and tools:
https://www.rand.org/research/projects/truth-decay/fighting-...
These lists have been frequently used in attempts to train ML models for detecting dis-/misinformation, but I think the results are somewhat questionable.
You can also enter into an endless debate over the reliability of the ranks and the rankers. Further limitations include limited geographic coverage, slow-pace curation and inability to pick-up "flash websites" designed for propaganda dissemination, and so forth.