Folders and Filters
This addon adds an entry in the right-click menu which re-threads selected messages together (groups selected messages into the same thread)". This is done by _modifying_ messages; the author of the addon declines any responsibility for data loss.
Inbox Cleaner of expired Emails Requires Restart
Moves expired Emails out of your Inbox!
Color Folders Requires Restart
Color your Folder Treeview Icons!
SmartFilters Requires Restart
Tired of writing a lot of filters? Install SmartFilters now to organise your mailbox automatically. It can sort out your mailing lists and robot emails.
SavedSearchInSubFolders Requires Restart
This addon allows virtual folders (saved searches) to automatically process all subfolders of their selected target folders.
The search targets are updated automatically whenever a new folder is added, or a virtual folder is updated.
Collapsed Unread Requires Restart
Shows unread email count for collapsed folders even if the unread mails are in subfolders.
Folder Levels Requires Restart
Rank your email folders by how much you care about them, and hide the ones you don't need right now.
CapsKiller Requires Restart
Caps Killer is a protection against newbies using caps in their mails.