Jenkins - Jenkins is an open-source continuous integration server with 300+ plugins to support all kinds of software development
Cakemail - Email marketing and transactional emails that deliver. Try it for FREE!
CircleCI - CircleCI gives web developers powerful Continuous Integration and Deployment with easy setup and maintenance.
Hatchbuck - SMB sales and marketing software
Travis CI - Focus on writing code. Let Travis CI take care of running your tests and deploying your apps.
MailChimp - MailChimp is the best way to design, send, and share email newsletters.