WiseStamp - WiseStamp allows you to easily create and implement slick and unique email signatures for your business.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.
NEWOLDSTAMP - Email signature generator
Constant Contact - Constant Contact offers email marketing, social media marketing, online survey, event marketing, digital storefronts, and local deals tools.
Exclaimer - Exclaimer is the industry's leading provider of email signature solutions, empowering businesses to unlock the potential of email as a key digital advertising channel.
Campaign Monitor - Email marketing software built for designers and their clients to run successful email campaigns.