Soulherder

Whenever a creature is exiled from the battlefield, put a +1/+1 counter on this creature.
At the beginning of your end step, you may exile another target creature you control, then return that card to the battlefield under its owner's control.

Getting

Azorius Signet

Dour Port-Mage

Whenever one or more other creatures you control leave the battlefield without dying, draw a card.
{1}{U}, {T}: Return another target creature you control to its owner's hand.

Gonti's Aether Heart

Whenever Gonti's Aether Heart or another artifact you control enters, you get {E}{E} (two energy counters).
Pay eight {E}, Exile Gonti's Aether Heart: Take an extra turn after this one.

Have

Wayfarer's Bauble

{2}, {T}, Sacrifice this artifact: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Jace, Memory Adept

+1: Draw a card. Target player mills a card.
0: Target player mills ten cards.
−7: Any number of target players each draw twenty cards.

Niko Aris

When Niko Aris enters, create X Shard tokens. (They're enchantments with "{2}, Sacrifice this token: Scry 1, then draw a card.")
+1: Up to one target creature you control can't be blocked this turn. Whenever that creature deals damage this turn, return it to its owner's hand.
−1: Niko Aris deals 2 damage to target tapped creature for each card you've drawn this turn.
−1: Create a Shard token.

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Horseshoe Crab

Inspired Inventor

When this creature enters, choose one —
• You get {E}{E}{E} (three energy counters).
• Put a +1/+1 counter on target creature.
• Create a 1/1 colorless Servo artifact creature token.

Entity Tracker

Flash
Eerie — Whenever an enchantment you control enters and whenever you fully unlock a Room, draw a card.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
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.)

Mox Amber

{T}: Add one mana of any color among legendary creatures and planeswalkers you control.

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Brightling

{W}: This creature gains vigilance until end of turn.
{W}: This creature gains lifelink until end of turn.
{W}: Return this creature to its owner's hand.
{1}: This creature gets +1/-1 or -1/+1 until end of turn.

Questioning

Loyal Inventor

Vigilance
When this creature enters, you may search your library for an artifact card, reveal it, then shuffle. Put that card into your hand if you control an Assassin. Otherwise, put that card on top of your library.

Propaganda

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Morphling

{U}: Untap this creature.
{U}: This creature gains flying until end of turn.
{U}: This creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
{1}: This creature gets +1/-1 until end of turn.
{1}: This creature gets -1/+1 until end of turn.

Teleportation Circle

At the beginning of your end step, exile up to one target artifact or creature you control, then return that card to the battlefield under its owner's control.

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Plains

Island

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Windfall

Each player discards their hand, then draws cards equal to the greatest number of cards a player discarded this way.

Volatile Stormdrake

Flying, hexproof from activated and triggered abilities
When this creature enters, exchange control of this creature and target creature an opponent controls. If you do, you get {E}{E}{E}{E}, then sacrifice that creature unless you pay an amount of {E} equal to its mana value.

Minister of Inquiries

When this creature enters, you get {E}{E} (two energy counters).
{T}, Pay {E}: Target player mills three cards.

Basilisk Collar

Equipped creature has deathtouch and lifelink. (Any amount of damage it deals to a creature is enough to destroy it. Damage dealt by this creature also causes you to gain that much life.)
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Chrome Mox

Imprint — When this artifact enters, you may exile a nonartifact, nonland card from your hand.
{T}: Add one mana of any of the exiled card's colors.

Minamo, School at Water's Edge

{T}: Add {U}.
{U}, {T}: Untap target legendary permanent.

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)