X1 lets you find text in emails, contacts, attachments and files fast.
E-mail Follow-Up can remind you if an email you sent did not receive a reply after a certain time, and it's easy to send a follow-up reminder to the original recipient, too.
Windows Search lets you find emails, attachments, contacts, files and more in an easily accessible yet flexible interface.
Save Message InboxRULES Action is a near-perfect solution for saving messages and attachments automatically and flexibly from Outlook to disk using Outlook's native rules engine or plugging right into Exchange Server.
Auto-Mate applies flexible rules to your Outlook folders (a number of smart filters are already included) periodically, automatically organizing your mail in the manner of a personal assistant.
Using Bayesian statistics, SpamAid achieves a great spam detection rate and is really easy to use.
Junk-Out is a great anti-spam plug-in for Outlook. It combines the simplicity of Bayesian filters that just get it right with lots of flexibility.
FreeBusy is a handy tool that responds to email in Outlook whenever you're not ready to answer at once (because of a vacation or a meeting, for example).
Attach Plus makes sending files via email easy and flexible by compressing documents or converting them to PDF files.
Copernic Desktop Search makes it easy to find any email in any Outlook or Outlook Express folder fast.