I believed this forum is a good start to review gambling platforms there are hundreds or maybe thousands of them launched their platform but only a few of them was survived and now still having a business here in the forum. I understand why you are looking for a gambling site to promote, it is very common in the gambling sector to have an affiliation.

You can visit this thread but this is a little bit outdated, it was updated last year. [Overview of all bitcoin casinos] Latest update: 14-03-19 VISIT NEW WEBSITE

Does your website has anything specific or associated with cryptocurrency? Gambling websites and casinos with bitcoin and other cryptocurrency acceptance do promotion through forums and other sources where it gets more visibility to the cryptocurrency users.