Unstable Mutation

Enchant creature
Enchanted creature gets +3/+3.
At the beginning of the upkeep of enchanted creature's controller, put a -1/-1 counter on that creature.

Tundra

Mana Short

Tap all lands target player controls and that player loses all unspent mana.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Counterspell

Plains

Disenchant

Jayemdae Tome

Sol Ring

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Savannah Lions

Recall

Discard X cards, then return a card from your graveyard to your hand for each card discarded this way. Exile Recall.

Braingeyser

Serendib Efreet

Flying
At the beginning of your upkeep, Serendib Efreet deals 1 damage to you.

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Island

Tolaria

{T}: Add {U}.
{T}: Target creature loses banding and all "bands with other" abilities until end of turn. Activate only during any upkeep step.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Power Sink

Counter target spell unless its controller pays {X}. If that player doesn't, they tap all lands with mana abilities they control and lose all unspent mana.

Control Magic

Enchant creature
You control enchanted creature.

Balance

Each player chooses a number of lands they control equal to the number of lands controlled by the player who controls the fewest, then sacrifices the rest. Players discard cards and sacrifice creatures the same way.