Pipedrive - Sales pipeline software that gets you organized. Helps you focus on the right deals, so easy to use that salespeople just love it. Great for small teams.
MailStore - MailStore Home - A 100% free single-private-user desktop solution
Zoho CRM - Omnichannel CRM for Businesses of all sizes
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
Freshsales CRM - A full-fledged CRM for high-velocity sales teams.
Gmvault - Backup the emails in your Gmail account.