My setup:
QWER - skills (main skills go here)
ASD - skills (secondary skills)
F - pick up items
RMB - movement skill or an attack that can’t be bound to LMB
LMB - main attack or force move, if attack can’t be bound
Space bar - usually some kind of heal or circuit breaker
Mouse 4 & 5 - more skills (usually a movement rune & life steal activation, or a debuff)
1 - heal potion
2 - energy potion
3 - rift
V - hide/show all items
Z - codex
X - toggle skill bar
C - character window
T - skill window
Tab - map
Camera zoom is unbound so I don’t accidentally press it and annoy myself, and I don’t use any pet keys either.
Basically a setup made to have almost everything in reach of your left hand without needing to move it much.
I tend to use something similar in other ARPGs and Dota, etc.