Imap

Microsoft Outlook 2013 15.0.4420.1017

Windows email client that uses SMTP and IMAP

PRO: Pulls contact info from online sources
CON: Monochromatic colors makes things hard to focus on
Vote: 5.3/10 (540 votes) Platform: Windows

SMS Backup 1.5.11

Backup SMS, MMS and call history to Gmail, Google Calendar or IMAP

Vote: 4.5/5 (94 votes) Platform: Android

eNotifyLite 4.111

Unique SMS and email alerts on your phone and smartwatch

Vote: 4.0/5 (54 votes) Platform: Android

Thunderbird Portable (en-US) 17.0.8

A mail client for mobile devices that supports POP and IMAP email account types 

PRO: Fits easily on a USB pen drive
CON: Synchronisation with mail server can be problematic
Vote: 4.8/10 (20 votes) Platform: Windows

BlueMail 1.9.7.21

Mail support via IMAP, ActiveSync, EWS, POP3 - Gmail, Yahoo, Outlook, Office365

Vote: 4.5/5 (43 votes) Platform: Android

Microsoft Office 2007 Service Pack 2 (SP 2) 1.0

Software pack that fixes bugs and updates Microsoft Office

… the ability to save files as PDF documents. Outlook has also been optimized and will now support IMAP and RSS …

PRO: Important improvements for Excel and Outlook
CON: File size
Vote: 6.4/10 (1263 votes) Platform: Windows

Revolver Mail 8.3.1

Secure email application targeted at small businesses

PRO: Lightweight and free to use
CON: Developer site is in German
Vote: 3.8/10 (3 votes) Platform: Windows

Zimbra Desktop 2.0.1

Do your work offline then sync your documents when ready to connect to the internet

PRO: Works with Yahoo!, Gmail and POP/IMAP servers
CON: Many features are slow to respond
Vote: 2.7/10 (8 votes) Platform: Windows

TouchMail

An email app for Windows users that makes getting your message quick and securely

PRO: Multiple account use
CON: Some printing issues
Vote: 8.2/10 (5 votes) Platform: Windows