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.
Roundcube - Web-based IMAP email client
ActiveCampaign - Integrated email marketing, marketing automation, and small business CRM. Send beautiful newsletters, setup behavioral based automations, and benefit from sales automation.
HEY - Email at its best, new from Basecamp.
Pardot - Salesforce B2B marketing automation
Mailo - Mailo is an email client where you can send and receive emails to and from anyone with an email address.