iNoJB - iNoJB, formerly iNoCydia, is an amazing Cydia alternative requiring no jailbreak!
API List - A collective list of APIs. Build something.
Apple App Store - Install apps on your iDevice via the App Store.
Abstract APIs - Simple, powerful APIs for everyday dev tasks
Cydia - An alternative app store for jailbroken devices.
Phantombuster - A marketplace of simple to use no-code APIs