Facebook Advertising for Crypto Startups

Regardless of its recent bad press, Facebook remains the best advertising system in terms of targeting. You can also reach people via Instagram, which FB owns.

However, if your business offerings are related to crypto, you'll need to fill out this "Cryptocurrency Products and Services Onboarding Request" form:
https://www.facebook.com/help/contact/532535307141067

Note that you cannot market ICOs or crypto related investments.