There aren't that many crypto companies types if you think about that. The major ones are exchanges, but they became mainstream and can advertise at a much greater scale than bitcointalk.
Casinos are a bit different as they suffer much greater restrictions when it comes to advertising, so they're much more keen on exploring non-standard advertising options (like signature campaigns).
Mixers were another type of business but we all know what happened to them  I still miss them.