OpenCart - A free shopping cart system. OpenCart is an open source PHP-based online e-commerce solution.s
WooCommerce - A freely available eCommerce plugin that enables shop facilities on your WordPress website. Functionality enabling extensions & beautiful themes available.
Jumpseller - Start Your Online Store! Grow your business.
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.
Maian Coin - Lightweight cryptocurrency shopping cart system
EvenCart - EvenCart is an open source hybrid/headless eCommerce software built on top of ASP.NET Core and Shopify Liquid.