OfficeIns is a tiny portable tool - a 39KB executable - which lists any Microsoft Office add-ins on the current system, and has options to disable, enable or tell you more about them.
Launch OfficeIns and it displays a vast amount of detail on your add-ins: name, description, developer, the Office app where it's used (Word, Excel, Outlook etc), its Start Mode (load at startup or on demand), file name, Registry key and more.
Clicking on any column header sorts by that field, and just being able to do that can be useful. Clicking "Software" groups add-ins by their Office application, for example, so you'll see at a glance where you might have a lot installed, and whether there are any you don't recognise, or maybe no longer need.
If you do spot some third-party tool you'd like to remove then it's best to use the original installer/ uninstaller, which should - in theory - properly clean up your system.
If that's not possible then a right-click OfficeIns option allows you to change the add-in's Start mode to "Disabled", "Load at Start", "Load on Demand" or "Load at First Time".
Experts who need more control will find right-click options to open the add-in and CLSID keys in Regedit (if these don't work, relaunch OfficeIns as an administrator).
You can view and manage add-ins from the various Office applications, but OfficeIns makes the process much quicker and easier.