Thraben Inspector

When this creature enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Sanctifier en-Vec

Protection from black and from red
When this creature enters, exile all cards that are black or red from all graveyards.
If a black or red permanent, spell, or card not on the battlefield would be put into a graveyard, exile it instead.

Sol Ring

The Wandering Rescuer

Flash
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Double strike
Other tapped creatures you control have hexproof.

Rest in Peace

When this enchantment enters, exile all graveyards.
If a card or token would be put into a graveyard from anywhere, exile it instead.

Intrepid Adversary

Lifelink
When this creature enters, you may pay {1}{W} any number of times. When you pay this cost one or more times, put that many valor counters on this creature.
Creatures you control get +1/+1 for each valor counter on this creature.

Tenth District Hero

{1}{W}, Collect evidence 2: This creature becomes a Human Detective with base power and toughness 4/4 and gains vigilance.
{2}{W}, Collect evidence 4: If this creature is a Detective, it becomes a legendary creature named Mileva, the Stalwart, it has base power and toughness 5/5, and it gains "Other creatures you control have indestructible."

March of Otherworldly Light

As an additional cost to cast this spell, you may exile any number of white cards from your hand. This spell costs {2} less to cast for each card exiled this way.
Exile target artifact, creature, or enchantment with mana value X or less.

Plains

Thalia, Heretic Cathar

First strike
Creatures and nonbasic lands your opponents control enter tapped.

White Orchid Phantom

Flying, first strike
When this creature enters, destroy up to one target nonbasic land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Thalia, Guardian of Thraben

First strike
Noncreature spells cost {1} more to cast.

Containment Priest

Flash
If a nontoken creature would enter and it wasn't cast, exile it instead.

Blossoming Calm

You gain hexproof until your next turn. You gain 2 life.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Usher of the Fallen

Boast — {1}{W}: Create a 1/1 white Human Warrior creature token. (Activate only if this creature attacked this turn and only once each turn.)

White Plume Adventurer

When this creature enters, you take the initiative.
At the beginning of each opponent's upkeep, untap a creature you control. If you've completed a dungeon, untap all creatures you control instead.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Castle Ardenvale

This land enters tapped unless you control a Plains.
{T}: Add {W}.
{2}{W}{W}, {T}: Create a 1/1 white Human creature token.

Hopeful Initiate

Training (Whenever this creature attacks with another creature with greater power, put a +1/+1 counter on this creature.)
{2}{W}, Remove two +1/+1 counters from among creatures you control: Destroy target artifact or enchantment.

Spellbook Vendor

Vigilance
At the beginning of combat on your turn, you may pay {1}. When you do, create a Sorcerer Role token attached to target creature you control. (If you control another Role on it, put that one into the graveyard. Enchanted creature gets +1/+1 and has "Whenever this creature attacks, scry 1.")