Source: http://lifehacker.com/learn-over-60-google-now-commands-with-this-infographic-1471859787
There are a ton of cool things you can do with Google Now, but with Google constantly adding more voice commands (and integrating Google Now even more with Android KitKat
If you say or type in "help" in Google Now, you'll only get a few examples, and Google's own voice commands list isn't that long. This graphic, created by trendblog.net, highlights many commands you probably already know, but it's a nice long and updated list, complete with easter eggs. Also, it's just a good reminder of how great Google Now can be as a personal assistant and quick information tool.
Here's the full graphic (click to expand, right-click to save):
Awesome List of Google Now Voice Commands - KitKat Updated | trendblog.net