Awesome GitHub Topics - Top 500 topics on GitHub that's filtered and categorized
GitNews Web - Trending repositories from GitHub, HackerNews & Reddit
git:logs - The definitive list of open source resources on Github
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.
Mailbrew - Automated email digests from Twitter, Reddit, YouTube & more
Ruby Toolbox - Explore and compare open source Ruby libraries