Cantrips, all based on the Eternal Mechanism:
Delay Target Creature
Activate Target Permanent (even if its not yours)
Remove Summon Sickness
Remove 1 Poison Counter
Return Target Creature you control to your hand/deck
Heal 1 Damage to self (this is directly in line with Entropy Shield)
Burrow a Creature you control
Give Creature you control +1 until end of turn
Turn your mark into Element of Target
These are all balanceable effects for the Eternal Mechanism