The Startup Way - The new book from Eric Ries, author of The Lean Startup
GrowthList - A crowd-sourced list of growth hacks
UI Playbook - The documented collection of UI components
GrowthHackers Projects - Growth collaboration software for teams 📈
50 UI Tips - Improve your UI/UX skills in an hour, for free
Marketing Examples - A gallery of real world marketing case studies. Updated every day.