Really Good Emails - A large collection of good product email design.
The Sales Handbook by Intercom - New ways to close more deals
Good Sales Emails - Best sales emails from great companies
The Remote Sales Survival Guide - The no bullsh!t guide to selling in a time of adversity
Great Email Copy - A dose of emails from around the web.
Inside SaaS Sales - 1000+ sales emails and voicemails from top SaaS companies