Electron App Store - There are many app stores available for many platforms.
API List - A collective list of APIs. Build something.
Secrets of the App Store - Maximize your presence on the App Store.
Phantombuster - A marketplace of simple to use no-code APIs
Shopify App Store - The most powerful ecommerce app store
The Unsplash API - No-limits, do-what-you-want API for access to 200K+ HD pics.