Various Greasemonkey scripts that enhance Gmail.

N.B. It is highly unlikely that any of these scripts still work; "new version of Gmail" refers to the late 2007 new version. There was a late 2011 revamp that changed Gmail's UI significantly. On the plus side, nearly all of these features are now available as either built-in features or Gmail Labs.

• Macros: adds more keyboard shortcuts (navigating to and applying labels, archiving, etc.) (more info)

• Conversation Preview: shows a preview bubble with a conversation contents while viewing the list of messages (i.e. without requiring navigation to another page) (more info)
• Fixed Font Toggle: adds a font toggle button so that messages can be viewed in a fixed-width font (more info)
• Label Colors: allows labels to be colored so they stand out more (more info)
• Macros: adds more keyboard shortcuts (for marking messages as read, moving them to the trash, applying labels, etc.) (more info, even more info)
• Google Reader Integration: adds a 'Feeds' links in the navigation area that opens up an embedded instance of Google Reader (more info)
• Saved Searches: lets you save search queries so you can re-run them easily (more info)