Vue Storefront - Open Source PWA for any eCommerce
Stripe: Apple Pay - One-touch payment on iOS
Square Online Checkout - Create easy pay links for whatever you're selling and start accepting payments everywhere online.
Shopify - Shopify is a powerful ecommerce platform that includes everything you need to create an online store and sell online. Try it free for 14 days.
Sign2Pay - Secure mobile payments with your signature.
WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.