Google Open Source - All of Googles open source projects under a single umbrella
Mapus - Open source map tool with real-time collaboration
Opensource Builders - Find open-source alternatives to commercial apps
Kalygo - Free, Open Source, Reusable Smart Contract Components
LaunchKit - Open Source - A popular suite of developer tools, now 100% open source.
Open Source Tools Stack! - Top 50+ open source tools to build your brand!