NeverBounce - Real-time email verification and cleaning to ensure emails never bounce.
Thunderbird - Thunderbird is a free email application that's easy to set up and customize - and it's loaded with great features!
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
Microsoft Outlook - Organize your world. Outlook’s email and calendar tools help you communicate, stay on top of what matters, and get things done.
clearout.io - Clearout Email Finder & Email Verification Service - Drive sustainable business growth by expanding your reach, lowering hard bounces, and improving deliverability rates.
eM Client - eM Client is a fully-featured email client for Windows and macOS with a clean and easy-to-use interface. eM Client also offers features for calendars, tasks, contacts, notes, and chat.