CoinGate - CoinGate is a payment gateway for Bitcoin, XRP, Litecoin, Ethereum and 50 other cryptocurrencies.
CoinPayments - Payment gateway providing buy now buttons, shopping carts, and more to accept Bitcoin, Litecoin, and other cryptocurrencies/altcoins on your website/online store.
NOWPayments - NOWPayments is a crypto payment gateway that supports more than 300 cryptocurrencies, including fiat, and offers simple tools to accept crypto payments, like a crypto payments API, plugins, invoices.
Coinbase - Bitcoin, safe and easy.
Swiss Bitcoin Pay - Accept Bitcoin in your business.
BTCPay Server - A free and open source server for merchants wanting to accept Bitcoin for their business.