Startup School - How to start a startup, by Y Combinator
Dashboard UI Kit - A modern & responsive dashboard UI kit for designers.
YC World - Explore Y Combinator companies by country
Now UI Kit - A beautiful Bootstrap 4 UI kit. Yours free.
Y Combinator Companies - Interactive list of all 1000+ YC companies
Bots UI Kit - Fully customizable Sketch UI Kit for Messenger Platform