Petit Hacks - Acquisition, retention, & revenue hacks used by companies
Really Good Emails - A large collection of good product email design.
Growth.Design Case Studies - Product tips… in a comic book format
Good Email Copy - Email copy from great companies.
POWr - POWr is a library of free and customizable forms, galleries, social streams, e-commerce, countdowns, and more.
Good Sales Emails - Best sales emails from great companies