Mammudeck - Mammudeck is a TweetDeck-like columnar interface to Mastodon/Pleroma.
Fnd - Browse Apple App Store and iTunes on the Web
Code4Freedom - The liberty based app store.
JazzMyApp - Let JazzMyApp surprise you with amazing apps everyday. Try it out yourself.
Apple App Store - Install apps on your iDevice via the App Store.
Knicket App Search - The future Wikipedia for Apps