Expanding all child elements using Alt + Click is super useful!
That is cool. I use dev tools all day long and it's great seeing finding out these little tips. The triggering of the pseudo class is helpful also, didn't know that was available.
You can also plugin your android phone to the computer with a USB cable, and sync your phone to DevTools so that you can use DevTools on the computer, but the changes appears on the phone.
You can also do this in safari with an iOS phone. Sometimes I have to use it when chrome's mobile emulation isn't cutting it.