[Wheresthebeef]

One my of favourite remotes to use with the Shield has been the Fire TV Stick remote. 

 Sadly the big feature is still missing. A power button.

Drives me mad having to click 3 or 4  to put the shield into standby. Totally intuitive to my family members as well

EDIT: found a nice little trick for this on the 2017 ONLY. Just click home and back quickly to go into standby.

https://nvidia.custhelp.com/app/answers/...and-tricks    

 This is actually not limited to 2017 model. 
My 2015 Shield on the latest 7.1 preview (and using the Fire TV stick remote) goes into sleep mode when I press home and back at the same time.