WebGazer - Monitor your website's availability with WebGazer, review its performance and get instant notifications when your website goes down. No installation required and free plan available.
Templates by Email Monster - Hundreds of free, responsive email templates. Pick and edit.
Oh Dear! - Website monitoring, without the hassle
Really Good Emails - A large collection of good product email design.
Freshworks - Delight your customers, from wherever you are
Good Email Copy - Email copy from great companies.