The Y Combinator Database - The definitive database of YC companies with all the metrics
Startup Stash - A curated directory of 400 resources & tools for startups
Startup School - How to start a startup, by Y Combinator
Content Marketing Stack - A curated directory of content marketing resources
Y Combinator Companies - Interactive list of all 1000+ YC companies
StartupResources.io - Tightly curated lists of the best startup tools