Aron, Benalia's Ruin

Menace (This creature can't be blocked except by two or more creatures.)
{W}{B}, {T}, Sacrifice another creature: Put a +1/+1 counter on each creature you control.

Halo Fountain

{W}, {T}, Untap a tapped creature you control: Create a 1/1 green and white Citizen creature token.
{W}{W}, {T}, Untap two tapped creatures you control: Draw a card.
{W}{W}{W}{W}{W}, {T}, Untap fifteen tapped creatures you control: You win the game.

Act of Heroism

Untap target creature. It gets +2/+2 until end of turn and can block an additional creature this turn.

Magewright's Stone

{1}, {T}: Untap target creature that has an activated ability with {T} in its cost.

Genesis Chamber

Whenever a nontoken creature enters, if this artifact is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Dauntless Aven

Flying
Whenever this creature attacks, untap target creature you control.

Burst of Energy

Altar of Dementia

Sacrifice a creature: Target player mills cards equal to the sacrificed creature's power.

Staff of Domination

{1}: Untap this artifact.
{2}, {T}: You gain 1 life.
{3}, {T}: Untap target creature.
{4}, {T}: Tap target creature.
{5}, {T}: Draw a card.

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Drumbellower

Flying
Untap all creatures you control during each other player's untap step.

Lulu, Loyal Hollyphant

Flying
At the beginning of your end step, if a permanent you controlled left the battlefield this turn, put a +1/+1 counter on each tapped creature you control, then untap them.
Choose a Background (You can have a Background as a second commander.)