Contamination

At the beginning of your upkeep, sacrifice Contamination unless you sacrifice a creature.
If a land is tapped for mana, it produces {B} instead of any other type and amount.

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.

Sunstone

{2}, Sacrifice a snow land: Prevent all combat damage that would be dealt this turn.

Null Brooch

{2}, {T}, Discard your hand: Counter target noncreature spell.

Ensnaring Bridge

Creatures with power greater than the number of cards in your hand can't attack.

Temporal Extortion

When you cast this spell, any player may pay half their life, rounded up. If a player does, counter Temporal Extortion.
Take an extra turn after this one.

Rings of Brighthearth

Whenever you activate an ability, if it isn't a mana ability, you may pay {2}. If you do, copy that ability. You may choose new targets for the copy.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

No Mercy

Whenever a creature deals damage to you, destroy it.

Xiahou Dun, the One-Eyed

Horsemanship (This creature can't be blocked except by creatures with horsemanship.)
Sacrifice Xiahou Dun, the One-Eyed: Return target black card from your graveyard to your hand. Activate only during your turn, before attackers are declared.

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Maralen of the Mornsong

Players can't draw cards.
At the beginning of each player's draw step, that player loses 3 life, searches their library for a card, puts it into their hand, then shuffles.