Ruby Toolbox - Explore and compare open source Ruby libraries
Humaaans - Mix-&-match illustrations of humans with a design library.
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
Handsome Illustrations - Create unique illustrations for websites & applications.
LibHunt - LibHunt tracks mentions of software libraries on relevant social networks. Based on that data, you can find the most popular projects and their alternatives.
Blush - Illustrations for everyone