A thoughtful person who goes by the handle Kitze has taken it upon himself to create an online directory of over 150 Google Now voice commands and their more than a thousand variations. His site, ok-google.io, must have had a lot of traffic yesterday as word of it got out on reddit; I wasn’t even able to connect to it until this morning.
I already knew at least one particularly useful command, the one where you can save a list to Google Keep and then say:
“Ok Google, add [item] to [list].”
And now, thanks to this guide, I also know that I can also use Google Now for device control—I can increase/decrease the screen brightness, toggle Bluetooth, even take a selfie. The site has many other categories of commands, including messaging, navigation, travel, weather, web browsing and others.
The list is very much a work in progress. Additions, typos, etc. can be reported to the author via github. There has also been a promise that the data will be open sourced soon, making it even more useful for the Android community.
Kudos to Kitze!