The Y Combinator Database - The definitive database of YC companies with all the metrics
Hoodmaps - Crowdsourced neighborhood 🗺 maps to navigate a city 💫
Startup School - How to start a startup, by Y Combinator
YouMap - The Human Atlas™
Y Combinator Companies - Interactive list of all 1000+ YC companies
Zenly - Zenly is a GPS tracker to locate your friends in realtime.