Allomani - Allomani is an E-Store with the shopping cart for online shopping websites, hosting & designing, Paid services, etc.
Gumroad - An all-in-one solution to sell your work and grow your audience.
OpenCart - A free shopping cart system. OpenCart is an open source PHP-based online e-commerce solution.s
Easy Digital Downloads - Easy Digital Downloads is a complete eCommerce solution for WordPress.
Selz - Seriously Simple Selling
Ko-fi - Ko-fi offers a friendly way for content creators to get paid for their work.