There are a lot of free databases of real crypto users and you can find the bounty section. So I don't see any reason to buy a database or mail list of crypto users.
This is a breach of privacy and its not good for those interested to buy this database as it will mark their project spam and they will be reported, I usually marked emails that are coming to me without an unsubscribe button and without my permission to send me promotions or anything similar, OP deserves a flag for selling information without those user's permission in our country we have a very strict law on this, you will be fine and go to jail for selling information without user's permission, that is why we should be too careful participating on projects that are not compliant.