StorePreviewer - See how your app will look like on the App Store
Startup School - How to start a startup, by Y Combinator
App Store Launch Stories - A podcast about the stories behind app launches
YC World - Explore Y Combinator companies by country
Retro App Store - How App Store would look like if it was launched in 80s
Y Combinator Companies - Interactive list of all 1000+ YC companies