Installer - Installer is a package manager build specifically for iOS. Older versions of Installer are Open Source
iNoJB - iNoJB, formerly iNoCydia, is an amazing Cydia alternative requiring no jailbreak!
Cydia - An alternative app store for jailbroken devices.
BuildStore - Safe and trustworthy alternative app store for iOS
Zestia - Zestia is a mobile app designed to assist you in organizing your hectic schedule, social life, and professional persona.
Apple App Store - Install apps on your iDevice via the App Store.