Change the volume of all devices
Change the volume of all devices, so you can change the volume of all devices at the same time not only a single device. For example if you wrote a routine called “night time” you could set all devices to a lower preset volume so as not to be so loud. Alternatively in the morning you could say “morning and all devices volume could be increased to a preset volume. And so on

-
Jose M. Alcaide commented
Yes! I have four Echos in different rooms, and I want to lower the volume at night on all of them. Currently, I need four routines. I would suggest to be able to select multiple devices, or even a multi room group to apply the volume change. In fact, the later can be done by a voice command, but not using a routine.
-
David Reisz commented
Yes. In my case, I'm looking to create the "Rock Out" Routine.
Me: "Alexa, time to rock out!"
Alexa sets volume on all Echo devices to 8.
Alexa: "OK, Dave""Really rock out" sets them all to 10.
"This is Spinal Tap" sets them to 11 :)