If you are buying things like op-amps you probably already know that there are only a limited number of companies that make them, particularly high performance ones.
You can go to parametric search at, say, Digikey, which might help you identify emergent suppliers, but it's also useful to go to the websites of the usual suspects (Analog.com (also includes Linear.com now), Ti.com etc.) and use their parametric search engines. Digikey is pretty good, but they still miss things like listing Vos typical values rather than worst-case. In the end you have to go to information such as datasheets and app notes from the real manufacturer.
Anything less is 2nd hand information, and that's not good enough. Personally, I don't think I would use a list contributed by volunteers on, say, Wikipedia.