bit.lySoftware by Base
MailStore - MailStore Home - A 100% free single-private-user desktop solution
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.
MailSteward - MailSteward : The Ultimate E-mail Manager for Mac OS X
Zoho CRM - Omnichannel CRM for Businesses of all sizes
Gmvault - Backup the emails in your Gmail account.
Copper - Copper (formerly ProsperWorks) is easy-to-use customer relationship management for small businesses. Capture contacts and sales leads direct from Gmail with our simple CRM.