Rated 5 out of 5 stars
I have used both Tab Utilities and Tab Mix Plus. Here are a few suggestions for TMP:
1. Incorporate a function to migrate the tab History of the original tab into the tab history of any tabs that are opened from it.
2. Allow marking Tabs as Read/Unread using context menu
3. In customisation options for Tab appearence, provide options to set a colored box around certain types of tabs.
4. Allow customisation of appearence of pinned/protected/locked tabs too