GameCopyWorld is very web 1.0 but it's still around if you need No CD cracks.
Serial keys...hmmm. That's a good question. serials.ws doesn't exist anymore.
I guess these days you'd look up a game on archive.org and look for a text file bundled into the release that has a key or two.
Fuck. That actually annoys me. We should have a serial / keygen archival website.