I don't think you can really do much better than Google. If the competitor/originator isn't on the first few pages, then you have an advantage even if you weren't the first one to make it.
If you're talking startups, I agree. But sometimes it's just some little library/tool that I need, and I'll spend an afternoon writing it and put it on GitHub if it doesn't exist, but if it does, I'd rather just use that than waste my time.