The Y Combinator Database - The definitive database of YC companies with all the metrics
Cyberleads - Find fast growing companies to do business with
Startup School - How to start a startup, by Y Combinator
DollarLeads.co - A monthly subscription/one-off lead generation SaaS focused on driving quality over quantity on leads. All leads are hand-picked and focus on companies that are willing to hire/outsource parts of their operations.
Y Combinator Companies - Interactive list of all 1000+ YC companies
SaasyDB - Lists of recently funded companies with verified employee email addresses, sent to you monthly