1. GMail
Gmail is the built-in email client that can be used to access your Google mail. It supports multiple accounts and can push new emails to your mobile.
This is a great option if your primarily email is gmail.
The dedicated Gmail application integrated with Contacts and Android applications.

  • Email pushed automatically to your phone
  • Search all your messages
  • Access synched messages when off line
  • View messages by conversation
  • Multiple Gmail accounts
  • Stars, labels, and many other features

2. K-9 Mail
K-9 is the best email client for Android(after gmail…). It’s incredibly powerful and 100% free.
K-9 Mail is an open-source e-mail client with search, IMAP push email, multi-folder sync, flagging, filing, signatures, bcc-self, PGP, mail on SD & more!
K-9 supports IMAP, POP3 and Exchange 2003/2007 (with WebDAV).
K-9 is a community developed project.

3. ProfiMail
ProfiMail is a powerful email client that supports POP, IMAP and SMTP. This was a success on the Symbian platform. The list of features is extensive and includes support for multiple accounts, push email (using IMAP IDLE), signatures, HTML email and excellent support for attachments.
The program was designed to be as simple as possible, while offering very easy control, and many useful functions, essential for comfortable work with your email.

Features:

  • Automatic synchronization of messages with the mail server
  • IMAP folders
  • Attachments – view, save, send
  • HTML messages with images and hyperlinks
  • Built-in File Explorer
  • Push email – instant notification about new messages (using IMAP IDLE)
  • Address book
  • Signatures
  • Support for POP3 / IMAP / SMTP mail servers
  • Writing mails using T9 dictionary (if available on phone)
  • Multiple email accounts
  • Rules and filters allowing selective message download
  • Opens and browses ZIP archives
  • Support for various character encoding – Western, Cyrillic, Central European, and more
  • Build-in image viewer for JPG, PNG and other popular formats
  • Text viewer for standard text, HTML and Word documents
  • Optimized for GPRS – get headers first, then download message bodies which you really want to see
  • Access Hotmail, Gmail, Yahoo mail, and other webmail accounts’ via POP3 or IMAP support
  • Scheduled message download
  • Sound notifications

4. TochDown
TochDown from Nitrodesk lets you access your corporate email, contacts, calendar and tasks right on your Android device. It supports Exchange, Zimbra, Kerio, Novell GroupWise and other servers used in corporate environments. Nitrodesk allows you to buy the licence directly from them in case your SIM card is from one of the many countries that are not allowed to buy apps on the Android Market.

Major Improvements in version 7

  • Expanded list of supported MDM solutions : Afaria, AirSync, FiberLink, MobileIron, NotifyMDM, SOTI, Zenprise, WaveLink.
  • Improved User interface for tablets
  • Ability to show summary of email body when viewing email list.
  • Improved multi select operations
  • Updated S/MIME security
  • Resizable, scrollable widgets for Honeycomb 3.1 devices
  • Improved battery life

For more feature list of tochdown visit here