Interfacer - Collection of more than 200+ free design resources
Nawvel - Nawvel is a handy-dandy library of tried, tested & curated resources.
Blush - Illustrations for everyone
Startup Network - Predicting successful startups using AngelList data
Facebook Design Resources - A collection of free resources made by designers at Facebook
Google Design Sprint Starter Kit - This Kit helps you to run your first Google Design Sprint.