Adds keyboard shortcuts to change folder, move/copy messages, with folder name auto-completion (using only the keyboard). Same for tags. Also includes a system of rules to suggest a target folder for saving messages; re-creates Eudora's Alt-Click; facilitates navigation in the 3-pane window; makes it easy to change between To/Bcc/Cc fields in the composer; facilitates tag-oriented operations. All that with the keyboard only!
Quickfile is an extension for Mozilla Thunderbird which initially aimed to speed up filing of messages into your mail folder heirarchy but now includes features for navigation and folder creation...