Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting
Google Open Source - All of Googles open source projects under a single umbrella
WebGazer - Monitor your website's availability with WebGazer, review its performance and get instant notifications when your website goes down. No installation required and free plan available.
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Troops Slack Sales Gong - The most customizable Salesforce Gong in Slack
Open Source @IFTTT - A collection of IFTTT OSS projects.