Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
FameBit - Easiest Way to Find, Hire, and Work with YouTube Influencers
Mailbird - Mailbird is the best email client for Windows 7, 8 and 10
Smarp - Smarp is an employee advocacy SaaS solution that turns employees into brand ambassadors and influencers.
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
inzpire.me - An end-to-end solution for influencer marketing