Not to mention potential application in blue-based control shells, but I do not anticipate those being extremely strong on release, especially compared to Merfolk
Creatures (11) Planeswalkers (4) Lands (26) Spells (19) Maybe this one is taking the plan to Cartouche our opponents creatures thing too far, but we can also just Cartouche our Zombie tokens
This ultimately forces a continual tax upon opponents that drains them of available land while providing the controller with additional mana resources
Conversely, power levels can be more abstract, like Commander Spheres Lasagna Tier: This obviously is much more open to interpretation when it comes to cards that are welcome and those that arent, but it places more emphasis on the enjoyment of the game than maintaining a prescriptive card pool or rule set
Not sure which fits your play style
Drannith Magistrate This card will probably not see play: Lorkac: The card is bad