Wall of Essence

Defender (This creature can't attack.)
Whenever Wall of Essence is dealt combat damage, you gain that much life.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle Elixir of Immortality and your graveyard into their owner's library.

Well of Lost Dreams

Whenever you gain life, you may pay {X}, where X is less than or equal to the amount of life you gained. If you do, draw X cards.

Teyo, the Shieldmage

You have hexproof. (You can't be the target of spells or abilities your opponents control.)
−2: Create a 0/3 white Wall creature token with defender.

Fortified Area

Wall creatures you control get +1/+0 and have banding. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Worship

If you control a creature, damage that would reduce your life total to less than 1 reduces it to 1 instead.

Aurification

Whenever a creature deals damage to you, put a gold counter on it.
Each creature with a gold counter on it is a Wall in addition to its other creature types and has defender. (Those creatures can't attack.)
When Aurification leaves the battlefield, remove all gold counters from all creatures.

Slaughter the Strong

Each player chooses any number of creatures they control with total power 4 or less, then sacrifices all other creatures they control.

Perimeter Captain

Defender
Whenever a creature you control with defender blocks, you may gain 2 life.

Fortified Rampart

Teyo, Aegis Adept

+1: Up to one target creature's base power perpetually becomes equal to its toughness. It perpetually gains "This creature can attack as though it didn't have defender."
−2: Conjure a card named Lumbering Lightshield onto the battlefield.
−6: You get an emblem with "At the beginning of your end step, return target white creature card from your graveyard to the battlefield. You gain life equal to its toughness."

Make a Stand

Creatures you control get +1/+0 and gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Plains

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.