Armored Ascension

Enchant creature
Enchanted creature gets +1/+1 for each Plains you control and has flying.

Skrelv, Defector Mite

Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Skrelv, Defector Mite can't block.
{W/P}, {T}: Choose a color. Another target creature you control gains toxic 1 and hexproof from that color until end of turn. It can't be blocked by creatures of that color this turn. ({W/P} can be paid with either {W} or 2 life.)

Take Up the Shield

Put a +1/+1 counter on target creature. It gains lifelink and indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Bathe in Light

Radiance — Choose a color. Target creature and each other creature that shares a color with it gain protection from the chosen color until end of turn.

Makeshift Binding

When Makeshift Binding enters, exile target creature an opponent controls until Makeshift Binding leaves the battlefield. You gain 2 life.

Apostle of Invasion

Flying
Corrupted — As long as an opponent has three or more poison counters, Apostle of Invasion has double strike.

Plains

Sandblast

Sandblast deals 5 damage to target attacking or blocking creature.

Moment of Heroism

Target creature gets +2/+2 and gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Second Breakfast

Up to two target creatures each get +2/+1 until end of turn. Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Celestial Purge

Serra Angel

Flying
Vigilance (Attacking doesn't cause this creature to tap.)

Zealot's Conviction

Flash
Enchant creature
Enchanted creature gets +1/+1.
Corrupted — As long as an opponent has three or more poison counters, enchanted creature gets an additional +1/+0 and has first strike.

Field Marshal

Other Soldier creatures get +1/+1 and have first strike. (They deal combat damage before creatures without first strike.)

Search the Premises

Whenever a creature attacks you or a planeswalker you control, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Temporal Isolation

Flash
Enchant creature
Enchanted creature has shadow. (It can block or be blocked by only creatures with shadow.)
Prevent all damage that would be dealt by enchanted creature.

Alabaster Mage

{1}{W}: Target creature you control gains lifelink until end of turn. (Damage dealt by the creature also causes its controller to gain that much life.)

Spirit Mantle

Enchant creature
Enchanted creature gets +1/+1 and has protection from creatures.

Stagecoach Security

When Stagecoach Security enters, creatures you control get +1/+1 and gain vigilance until end of turn.
Plot {3}{W} (You may pay {3}{W} and exile this card from your hand. Cast it as a sorcery on a later turn without paying its mana cost. Plot only as a sorcery.)