archfiend of ifnir - If you want to proliferate -1/-1 counters on your opponent's creatures. You're commander proliferates by discarding so you can stack the triggers so that you get MAX value out of the two.
bloodtracker - All you have to do is pay life one time realistically and as long as you're proliferating you'll be getting a stronger creature on the board and net you mass value when it leaves.
Cordial Vampire - if you lean into mono-black vampire tribal it'll allow for you to focus on proliferating the +1/+1 counters on your vamps and grow them quickly.
Embodiment of agonies - If your graveyard is already stacked then it'll enter the field pretty large off the rip. The once you start proliferating he'll only get larger.
Flesh carver - when he dies he'll replace himself with a creature based off his power. Sac a creature, get the counter, proliferate from there.
Marionette master - If you run any artifact creatures or if you have a method of popping out servos/thopters consistently you can use them as sac fodder to your commander & burn your opponents for damage by proliferating the master's +1/+1 counters.
Midnight Banshee - Playing a mono-black deck means no negative draw back on your part. Make the -1/-1 counters on your opponent's creatures and then proliferate them.
Necroskitter - If you are dropping -1/-1 counters on your opponent's creatures consistently what better method of manipulating the board then to kill AND steal their creatures.
Noosegraf Mob - Proliferating this card will constantly give you a board state of zombies which can buffer your life total while putting pressure on your opponent. Run it with a
Hell's Caretaker and you'll have a combo for creating your board state.
Oathsworn Knight - Give him counters by proliferating and you'll be able to stack his power and
lay waste to people's creatures. Give him death touch for extra value. The same could be done with the
unbreathing horde as well.
Ob Nixilis unshackled - It serves as a deterrent against your opponents tutoring so much and as you're doing your aristocrats playstyle you're making him stronger as well. Play him with
grave pact and you can manipulate the board state as well.
Wall of limbs - if you want a blocker that keeps growing AND can wipe a player's life total then this would be something worth proliferating and running.
With
Yawgmoth, Thran Physician you have quite a bit of options on your hands, what are your thoughts on these choices?