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.)

Faceless Haven

{T}: Add {C}.
{S}{S}{S}: Faceless Haven becomes a 4/3 creature with vigilance and all creature types until end of turn. It's still a land. ({S} can be paid with one mana from a snow source.)

Surge of Salvation

You and permanents you control gain hexproof until end of turn. Prevent all damage that black and/or red sources would deal to creatures you control this turn.

Solemnity

Players can't get counters.
Counters can't be put on artifacts, creatures, enchantments, or lands.

Axis of Mortality

At the beginning of your upkeep, you may have two target players exchange life totals.

Blacksmith's Skill

Target permanent gains hexproof and indestructible until end of turn. If it's an artifact creature, it gets +2/+2 until end of turn.

Gideon of the Trials

+1: Until your next turn, prevent all damage target permanent would deal.
0: Until end of turn, Gideon of the Trials becomes a 4/4 Human Soldier creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.
0: You get an emblem with "As long as you control a Gideon planeswalker, you can't lose the game and your opponents can't win the game."

The Book of Exalted Deeds

At the beginning of your end step, if you gained 3 or more life this turn, create a 3/3 white Angel creature token with flying.
{W}{W}{W}, {T}, Exile The Book of Exalted Deeds: Put an enlightened counter on target Angel. It gains "You can't lose the game and your opponents can't win the game." Activate only as a sorcery.

Snow-Covered Plains

Tamiyo's Safekeeping

Target permanent you control gains hexproof and indestructible until end of turn. You gain 2 life. (A permanent with hexproof and indestructible can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)

Snow-Covered Forest

Staff of Nin

At the beginning of your upkeep, draw a card.
{T}: Staff of Nin deals 1 damage to any target.