Common Cause

Nonartifact creatures get +2/+2 as long as they all share a color.

Absolute Law

Defend the Hearth

Prevent all combat damage that would be dealt to players this turn.

Commencement of Festivities

Everybody Lives!

All creatures gain hexproof and indestructible until end of turn. Players gain hexproof until end of turn. Players can't lose life this turn and players can't lose the game or win the game this turn.

Thran Weaponry

Echo {4} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
You may choose not to untap this artifact during your untap step.
{2}, {T}: All creatures get +2/+2 for as long as this artifact remains tapped.

Repay in Kind

Each player's life total becomes the lowest life total among all players.

Arbiter of Knollridge

Vigilance
When this creature enters, each player's life total becomes the highest life total among all players.

Chameleon Blur

Prevent all damage that creatures would deal to players this turn.

Everlasting Torment

Players can't gain life.
Damage can't be prevented.
All damage is dealt as though its source had wither. (A source with wither deals damage to creatures in the form of -1/-1 counters.)

Absolute Grace

All creatures have protection from black.

Mycosynth Lattice

All permanents are artifacts in addition to their other types.
All cards that aren't on the battlefield, spells, and permanents are colorless.
Players may spend mana as though it were mana of any color.