Gumroad - An all-in-one solution to sell your work and grow your audience.
Piano - Piano lets you quickly learn the piano or other musical instruments using cell phones and tablets, and also contains magic tiles and different mini-games.
Payhip - Sell digital downloads, courses, coaching, and more from one simple platform.
Guitar - Git GUI Client. Open Source, Free Software (GPL v2). Run on Windows, macOS and Linux.
robora - Robora is a service which aims to help you sell anything, anyway you like.
Stripe - Online payment processing for internet businesses. Stripe is a suite of payment APIs that powers commerce for online businesses of all sizes. Use Stripe’s payment platform to accept and process payments online for easy-to-use commerce solutions.