BTCPay Server - A free and open source server for merchants wanting to accept Bitcoin for their business.
Bisq - Bisq is an open-source desktop application that allows you to buy and sell bitcoins in exchange for national currencies, or alternative cryptocurrencies.
ALFAcoins - A secure payment gateway for cryptocurrencies
Binance - Cryptocurrencies exchange platform
CoinGate - CoinGate is a payment gateway for Bitcoin, XRP, Litecoin, Ethereum and 50 other cryptocurrencies.
Coinbase - Bitcoin, safe and easy.