CS183B - Startup Class - Stanford class taught by Sam Altman & guest speakers
The Y Combinator Database - The definitive database of YC companies with all the metrics
YC Startup Class - A live, one-hour class by Sam Altman on Platzi
Y Combinator Companies - Interactive list of all 1000+ YC companies
Google Classroom - Learning management tool by Google
Startup School - How to start a startup, by Y Combinator