Postbox
Read your mail and synchronize your Gmail, Hotmail, etc.
ProductiveMail
Check that your emails are received and read
Reach-a-Mail
Take your emails on a portable device
Revolver Mail
Combines the management of emails, agenda and calendar
Robomail
Restrictions
50 trial emails
SafeMail
Copy all your messages and addresses from Outlook
Scott's Gmail Alert
Receive notifications from Gmail, Google Apps, Google Calendar and RSS feeds
SendMail
Automatically send attachments by email
SendTools
Schedule the sending of emails in Thunderbird
yes Email
Attractive tabbed email client
SmarterMail
A good option for receiving emails
Sohails Gmail Notifier for Google Apps
Check the emails of your Google Apps account
Spam Bully
Restrictions
The trial version lasts 14 days.
Spam Monitor
Restrictions
Time-limited trial version
SpamAware
Powerful spam filter in Outlook
SpamBayes
Prevent annoying spam from reaching your email account
SpamExperts Desktop
Prevent your email account from being filled with spam
SPAMfighter
Block the arrival of SPAM to your Outlook Express
Spamihilator
Powerful anti-spam filter for your email account