GitHub + Slack Integration - Full visibility into your GitHub projects right inside Slack
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.
GitCommands - An interactive reference tool for Git commands
Ruby Toolbox - Explore and compare open source Ruby libraries
ask-stack - Get answers from Stack Overflow directly in the Atom editor
GitNews Web - Trending repositories from GitHub, HackerNews & Reddit