TabHistory
I often find that I have many many tabs open and that I want to switch amongst a certain number of tabs. Often these tabs aren't next to each other so the normal Ctrl+Tab and Ctrl+Shift+Tab stuff doesn't work out too well.
TabHistory provides two histories of the tabs.
The first history is automatic. Whenever you change tab, the tab you change to will be added to this history. To go back to the previous tab, press Ctrl+, (Ctrl+comma). To go to the next tab in the history, press Ctrl+. (Ctrl+dot).
The second history is manual. To add a tab to this history press Ctrl+Shift+M (think "mark tab"). To go back to the previous tab in this history press Ctrl+Shift+, and to go to the next tab in this history press Ctrl+Shift+.
This saves you from the situation of having many many tabs open and not being able to remember which one you were previously at and thus having to spend ages searching through all your open tabs.
Version 0.9.2 (Install) (5KB).
Firefox 1.5 - 2.0.0.*
This version is exactly the same as 0.9.1 but it can be installed in Firefox 2.
Version 0.9.1 (Install) (5KB).
Firefox 1.5 - 1.5.0.*
This version fixes a tiny behavioural bug in version 0.9 that allowed duplicate tabs to enter the history successively.
Version 0.9 (Install) (5KB).
Firefox 1.5 - 1.5.0.*
This version works under Firefox 1.5, has been quite comprehensively rewritten and allows customisation of the key bindings.
Version 0.5.1 (Install) (4KB).
Firefox 1.0 - 1.0.7
This is the first version that ever got published. There is no ability to rebind keys and it's not that well written. It does nevertheless work.