[2022] For the Mechanist players if your Mech runs off to Narnia.

I've bound 'Attack My Target', 'Return to Me', and the passive/active toggle all to my mouse wheel. It's made pet management a lot of fun. (My mouse has buttons for tilting the wheel left and right, which helps!)
I'm using:
Tilt Wheel Left: Attack My Target
Tilt Wheel Right: Return to Me
Press Wheel: Toggle passive/active

I feel really fancy in raids being able to seamlessly sic my mech on things like flame turrets in Sabetha, orbs on Gorseval, pawns in MO, etc, while I'm staying on the boss.