SaaS 1000 - Free exportable list of the fastest growing SaaS companies
Really Good Emails - A large collection of good product email design.
Ultimate SaaS Guide - 100 Q&A asked around scaling, sales and raising capital.
Good Email Copy - Email copy from great companies.
Saasler - Build SaaS integrations in days or weeks — not months
Good Sales Emails - Best sales emails from great companies