Wonder for Slack - Remember the things your team forgets
GitNews Web - Trending repositories from GitHub, HackerNews & Reddit
Read Something Great - A fun tool to help fix your information diet.
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.
Qikipedia - Instant Wikipedia summary cards on any web page
Ruby Toolbox - Explore and compare open source Ruby libraries