What are some alternatives?
When comparing How to Nail Cold Email and Growbots Email Timing Optimizer, you can also consider the following products
Good Email Copy - Email copy from great companies.
Great Email Copy - A dose of emails from around the web.
Really Good Emails - A large collection of good product email design.
EmailDrips - Get inspired by examples of email sequences
Templates by EmailOctopus - Free (do whatever you want) responsive email templates
Good Sales Emails - Best sales emails from great companies