WiseStamp - WiseStamp allows you to easily create and implement slick and unique email signatures for your business.
Customer.io - We make it easy to send emails triggered by user behavior. Build, measure and improve your emails to activate and retain users
MySignature - MySignature is FREE Email Signature Generator that helps to create Professional Signatures for major email clients such as Outlook, Gmail...
HubSpot - Grow Better With HubSpot: Software that's powerful, not overpowering. Seamlessly connect your data, teams, and customers on one CRM platform that grows with your business.
Sigstr - Email signature marketing
MailChimp - MailChimp is the best way to design, send, and share email newsletters.