OE Duplicate Remover   
http://ajsystems.com

If you use Outlook Express for your personal or business mail you will, no doubt, have encountered duplicate email messages. The "Outlook Express Duplicate Message Remover" will automatically find and remove duplicate messages. The OEDMR will (a) find duplicate messages in any folder or group of folders; (b) match messages based on mulltiple conditions; (c) search by date or date range; (d) display, delete, or move the duplicates.

MailList Manager   
http://www.AdvertiserTools.com

MailList Manager is a tool for organize your emails lists. MailList Manager have many great features, such as merge lists, sort, remove duplicates, special filters and formats. MailList Manager have made managing lists of quick and easy. MailList Manager know how to Merging Lists, how to Split lists with size volume and Split Lists with domain filter. Remove Duplicates and Filter for Emails from one list specified into another list. MailList Manager can filter Emails with specified parameters from result lists. MailList Manager have Alphabetical Sort, Domain Sort, User Name or company sort features. Save Result with different formats - One Email per line format or separate mails by TAB or by Commas. Show Statistics for end list MailList Manager.

EMailing List Pro   
http://petor.lab6.com

EMailing List Pro is a program for creating and managing lists of contacts (large or small), and then sending identical EMails out to all the people on the contact list. Includes many useful features, such as sort, search, select, etc. EMailing List Pro can save contact lists to files, and export and import Text and CSV files. It has many options for filtering contacts, e.g. prevent duplicates being added, and prevent contacts with invalid email addresses being added. Has support for Mail Merge, HTML format emails, File attachments, and Advanced scheduling.

Add-ins for Microsoft Office Outlook   
http://soft.ria-media.com.ru

RIA-Media Add-ins for Microsoft Office Outlook: Redirect, Duplicates, Attachments.

Auto BCC   
http://www.office-addins.com

Outlook Auto BCC is an add-in for Microsoft Outlook 2000/2002 (XP)/2003 that allows routing your outgoing messages through fast and simple rules. The Outlook Auto BCC features list: - Integrated directly into Outlook's Outbox; - Performs Blind Carbon Copy (BCC) or/and Carbon Copy (CC) automatically; - Supports rules based on the Account Name, Subject, Attached file names and To fields; - Supports multiple recipients; - Excludes duplicates from the To, CC and BCC fields.