GitNews Web - Trending repositories from GitHub, HackerNews & Reddit
SmallDevTools - Handy developer tools with a delightful interface
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.
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Ruby Toolbox - Explore and compare open source Ruby libraries
TextLab - TextLab is the fastest way to format, prettify, transform, hash, encode, and decode your data instantly!