Tab Options (formerly Tabkeys) lets you assign custom keyboard shortcuts for common tab actions in Safari. Available actions are: open a new tab, close the current tab, reload the current tab, switch to the next or the previous tab, move the current tab to the left or to the right. For each action, you can assign up to three characters as shortcuts (including ones that you type in combination with the Shift or Option key). For example, you could assign lowercase "w", uppercase "W", and Option+C to Close Tab. Only character keys are supported, either alone or in combination with Command, Option, and/or Shift. Not supported are special keys such as Home, PageDown, NumLock, and the arrow keys. Tab Options has a setting that determines where new tabs go when you open them using your chosen hotkey. You can opt to have new tabs open to the right of the current tab, to the left, or at the end of the tab bar. (Note that this setting does not affect tabs that are opened using any of Safari's built-in methods.) Another Tab Options setting determines which tab becomes active when you close a tab using your chosen hotkey. You can opt to have the left tab or the right tab become active. (Note that this setting does not apply when you close a tab using any of Safari's built-in methods.)
What is new in this release:
Fixed a crashing bug when tab positioning is used in Safari 9.
What is new in version 3.2.1:
Clinton String (clintxs on github) fixed a bug wherein cycling tabs in focus order would do the same in every window, not just the current one.
What is new in version 3.2:
Tab Options now supports using number key combinations to switch directly to any of the first ten tabs. The default combo is Control+number, but you can choose other modifiers in the Options page, or disable this feature entirely.
Unfortunately, I could not find a way to override Safari's default behavior for Command+number combinations, which are used to open Favorites. Also note that if you use Command-Shift or Command-Control as the modifiers, and you switch to tab 3 or 4, you will also be taking a screenshot, unless you change the screenshot hotkeys in System Preferences.
What is new in version 3.1.4:
Tweaked the keypress handler so hotkey presses are not propagated to the web page. Hopefully without messing anything up.