I have quite a lot of CSS races that I may be able to share with you. I don't have a CSGO server to test them on however, so can't guarantee particular functionality on CSGO.
I may not be able to give you some of them (As they have been coded specifically for our server), however if you come up with a list of some races you'd like I'd be happy to talk to you about whether I think they will work on CS:GO, and how much you're willing to pay for them