Two Factor Auth (2FA) - List of websites and whether or not they support 2FA
Coinbase - Bitcoin, safe and easy.
X (Twitter) - Connect with your friends and other fascinating people. Get in-the-moment updates on the things that interest you. And watch events unfold, in real time, from every angle.
Binance - Cryptocurrencies exchange platform
Rapid 2FA - A painless way to add two-factor authentication to your site
Poloniex - US-based cryptocurrency exchange with maximum security