CoinPayments - Payment gateway providing buy now buttons, shopping carts, and more to accept Bitcoin, Litecoin, and other cryptocurrencies/altcoins on your website/online store.
BitPay - Bitcoin payment gateway. Enterprise-grade solutions, from the pioneer of bitcoin payments.
CoinGate - CoinGate is a payment gateway for Bitcoin, XRP, Litecoin, Ethereum and 50 other cryptocurrencies.
BTCPay Server - A free and open source server for merchants wanting to accept Bitcoin for their business.
Bubble by V0LT - A self hosted, privacy respecting BitcoinCash store written in PHP
Plisio.net - Plisio is a Payment Service Provider (PSP) for merchants accepting crypto. Plisio enables your customers to pay with Bitcoin, Litecoin, Ethereum, Dogecoin, Zcash and 50 other cryptocurrencies.