Partner with Rory Williams (When this creature enters the battlefield, target player may put Rory into their hand from their library, then shuffle.)

Whenever Amy Pond deals combat damage to a player, choose a suspended card you own and remove that many time counters from it.

Doctor’s companion (You can have two commanders if the other is the Doctor.)

Flying

Bloatfly Swarm enters the battlefield with five +1/+1 counters on it.

If damage would be dealt to Bloatfly Swarm while it has a +1/+1 counter on it, prevent that damage, remove that many +1/+1 counters from it, then give each player a rad counter for each +1/+1 counter removed this way.

Magma Pummeler enters the battlefield with X +1/+1 counters on it.

If damage would be dealt to Magma Pummeler while it has a +1/+1 counter on it, prevent that damage and remove that many +1/+1 counters from it. When one or more counters are removed from Magma Pummeler this way, it deals that much damage to any target.

Magnanimous Magistrate enters the battlefield with five reprieve counters on it.

Whenever another nontoken creature you control dies, if its mana value was 1 or greater, you may remove that many reprieve counters from Magnanimous Magistrate. If you do, return that card to the battlefield under its owner’s control.

Polukranos enters the battlefield with six +1/+1 counters on it. It escapes with twelve +1/+1 counters on it instead.

If damage would be dealt to Polukranos while it has a +1/+1 counter on it, prevent that damage and remove that many +1/+1 counters from it.

{1}{B}{G}: Polukranos fights another target creature.

Escape—{4}{B}{G}, Exile six other cards from your graveyard.

Protean Hydra enters the battlefield with X +1/+1 counters on it.

If damage would be dealt to Protean Hydra, prevent that damage and remove that many +1/+1 counters from it.

Whenever a +1/+1 counter is removed from Protean Hydra, put two +1/+1 counters on it at the beginning of the next end step.

Sekki, Seasons’ Guide enters the battlefield with eight +1/+1 counters on it.

If damage would be dealt to Sekki, prevent that damage, remove that many +1/+1 counters from Sekki, and create that many 1/1 colorless Spirit creature tokens.

Sacrifice eight Spirits: Return Sekki from your graveyard to the battlefield.

Ugin’s Conjurant enters the battlefield with X +1/+1 counters on it.

If damage would be dealt to Ugin’s Conjurant while it has a +1/+1 counter on it, prevent that damage and remove that many +1/+1 counters from Ugin’s Conjurant.