I often use Start + D to quickly navigate to my desktop, Start + R to run cmd to ping servers and see if my internet is performing alright, Start + I to open settings, and Start + S to open Cortana for searching purposes.
I sometimes use Start + left/right arrow to snap apps into windows when I'm multitasking, but I'd like to highlight the word sometimes because I prefer to run the apps i.e. Readit, Groove, Photos, et al. in fullscreen because I'm not so used to multitasking, and I find Alt+Tabbing to be faster, maybe because I'm used to using it.
Oh, let's not forget the Messianic button combo of Alt + Ctrl + Delete. Solves everything 99% of the time.