On Slack by Standuply - The most extensive book on using Slack to the utmost
Velocity.js - Velocity is a JavaScipt animation engine.
Marketing for Startups - 47 practical tactics to get customers and achieve hockey stick growth.
CS183B - Startup Class - Stanford class taught by Sam Altman & guest speakers
Backchannel Chat - Backchannel Chat is best in class discussion tool that is intended for teachers to streamline their class activities.
The Startup Playbook - How-to guide for building your startup from the ground up