Phyrexian Unlife

You don't lose the game for having 0 or less life.
As long as you have 0 or less life, all damage is dealt to you as though its source had infect. (Damage is dealt to you in the form of poison counters.)

Toymaker

{1}, {T}, Discard a card: Target noncreature artifact becomes an artifact creature with power and toughness each equal to its mana value until end of turn. (It retains its abilities.)

Teferi's Protection

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.)
Exile Teferi's Protection.

Lethal Vapors

Whenever a creature enters, destroy it.
{0}: Destroy this enchantment. You skip your next turn. Any player may activate this ability.

Greater Auramancy

Other enchantments you control have shroud. (A permanent with shroud can't be the target of spells or abilities.)
Enchanted creatures you control have shroud.

Delaying Shield

If damage would be dealt to you, put that many delay counters on this enchantment instead.
At the beginning of your upkeep, remove all delay counters from this enchantment. For each delay counter removed this way, you lose 1 life unless you pay {1}{W}.

Voltaic Construct

Chronosavant

{1}{W}: Return this card from your graveyard to the battlefield tapped. You skip your next turn.

Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

Grand Abolisher

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.