Startup Security Program by Templarbit - Security practices & tools required to close large deals
Really Good Emails - A large collection of good product email design.
Google Capture the Flag 2017 - Google's 2nd annual worldwide security competition
Good Sales Emails - Best sales emails from great companies
SaaS 1000 - Free exportable list of the fastest growing SaaS companies
Great Email Copy - A dose of emails from around the web.