Snopes for possible wind-ups/fake news
Byline Times for news accuracy - not infallible but a good place to start.
Google Scholar for fact checking when what seem to be spurious claims are made, and Academia.edu if they are supposedly based on research.
Otherwise, places like the NHS website, and addresses with .gov or '.ac.uk' in the url. I'm wary of .com ones, as they are commercial, but as always, it depends what I'm looking for.
Like most, probably, I tend to start with Google if it's a general 'who's he again? What else was he in?' sort of query, and I love Shazam for finding music I only know by the tune.
I sometimes check police accounts on Twitter if there are rumours on local FB about things supposedly happening in the area. Again, they aren't going to compromise an inquiry, but it's surprising what does go on there.