Spark Mail - Spark helps you take your inbox under control. Instantly see what’s important and quickly clean up the rest. Spark for Teams allows you to create, discuss, and share email with your colleagues
Nawvel - Nawvel is a handy-dandy library of tried, tested & curated resources.
mlist - Email newsletters, outside of the inbox
Startup Network - Predicting successful startups using AngelList data
TL;DR Email - Send short emails & read emails as fast as you read Facebook
Google Design Sprint Starter Kit - This Kit helps you to run your first Google Design Sprint.