Do Things That Don't Scale - Discover new unscalable ways to grow your startup
Founder Society - An invitation-only organization of entrepreneurs
GrowthList - A crowd-sourced list of growth hacks
Single Founder Handbook - A step-by-step guide for bootstrapped software entrepreneurs
Transistor Game - Transistor is an Action-Adventure, Combat, Turn-based Strategy, Sci-Fi and Single developed and published by Supergiant Games.
Zero to Sold - How to start, run, and sell a bootstrapped business