SendX still works best for crypto email marketing
Since a lot of email marketing provides do not allow you to use certain types of content, including crypto, bitcoin and blockchain there are a few good providers out there that do. Providers like Mailchimp block certain types of email marketing crypto content as well as some gambling content.
SendX allows just this and its well priced and easy to use. It also give you a free trial and has an AI powered email marketing platform.