by Some key strokes are hard to mind or just inconvinient. But thanks of USB capable Arduino compatible boards, you can make your very own customized little side keyboard.
Software on my Github account: https://github.com/bitlischieber/MacroKeys/
File for the case on my Thingiverse account: https://www.thingiverse.com/thing:2953199
Partlist (or, what i used):
1 x Teensy 3.1 board
1 x USB micro cable
12 x Switches
12 x Keycaps
12 x Standard diodes (e.g. 1N4148)
Pieces of wire