I have been able to explore this a bit, though I still have not found a list. The voice commands are extremely limited. It's missing basics on Garmin, and my 2005 (7 years ago!) Toyota Prius, including:
* Retail Stores: Can't tell it to find the nearest Costco, for example
* Temperature: Can't tell it to set the A/C at 74 degrees (this has been in the Prius forever)
If you have the slightest foreign language accent (or other "accent" or dialect) it will not take your commands ... Toyota/Lexus TMC is also trying to figure out, how to fix this issue, they have the same problem. There is a technology out there (not yet fully developed in the automobile market) - where you can record your own commands. The drawback is that the unit will then listen only to you!