I found one that I use often in assemblies to check how many DOF or Degrees of Freedom are on a part.
Another really cool one is the ability to sort out your model tree alphabetically.
These can be found in the install path for your Inventor software.
i.e. – C:\Program Files\Autodesk\Inventor 2009\SDK
Run the user tools install.
Then look here:
C:\Program Files\Autodesk\Inventor 2009\SDK\UserTools\AssemblyTools
Jim……Another INCAT CAD Geek.