1)   PstDiff 1.0
Outlook PstDiff finds the difference between two pst files.

 2)   Backup Outlook 1.0.1
Backup and restore your Outlook quick and easy. Your mails, appointments, journal, tasks, notes and contacts are saved. Furthermore your email accounts and other settings are included in the backup.

 3)   CodeTwo PST Ghostbuster 1.0.1
CodeTwo PST Ghostbuster is a free tool to remove duplicate PST files in Outlook. This simple tool developed by CodeTwo software company allows removing duplicated PST files in Outlook with a single click.

 4)   NetWrix Exchange Mail Archiver 1.1.158
NetWrix Exchange Mail Archiver is a freeware email archiving and eDiscovery product for Microsoft Exchange that enables efficient email storage management and simplifies handling of litigation requests. The commercial version is also available.

 5)   PST Repair Tool 3.0
PST Repair Tool - Stellar Outlook PST Repair - repair corrupt .pst files that the Outlook Inbox Repair Tool fails to fix. Recover emails, contacts, calendar events, notes, journal entries, tasks. Free download lets you try on your own .pst files.