Intruder Alarm

Creatures don't untap during their controllers' untap steps.
Whenever a creature enters, untap all creatures.

Ashnod's Altar

Kapsho Kitefins

Flying
Whenever Kapsho Kitefins or another creature you control enters, tap target creature an opponent controls.

Junk Winder

Affinity for tokens (This spell costs {1} less to cast for each token you control.)
Whenever a token you control enters, tap target nonland permanent an opponent controls. It doesn't untap during its controller's next untap step.

Omen Hawker

{T}: Add {C}{U}. Spend this mana only to activate abilities.

Opposition

Tap an untapped creature you control: Tap target artifact, creature, or land.

Elvish Mariner

Whenever Elvish Mariner attacks, scry 1.
Whenever you scry, tap up to X target nonland permanents, where X is the number of cards looked at while scrying this way.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Anointed Procession

If an effect would create one or more tokens under your control, it creates twice that many of those tokens instead.

Frost Titan

Whenever Frost Titan becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {2}.
Whenever Frost Titan enters or attacks, tap target permanent. It doesn't untap during its controller's next untap step.

Hylda of the Icy Crown

Whenever you tap an untapped creature an opponent controls, you may pay {1}. When you do, choose one —
• Create a 4/4 white and blue Elemental creature token.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Gadwick, the Wizened

When Gadwick, the Wizened enters, draw X cards.
Whenever you cast a blue spell, tap target nonland permanent an opponent controls.

Verity Circle

Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, you may draw a card.
{4}{U}: Tap target creature without flying.

Freed from the Real

Enchant creature
{U}: Tap enchanted creature.
{U}: Untap enchanted creature.

Pemmin's Aura

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

Eldrazi Displacer

Devoid (This card has no color.)
{2}{C}: Exile another target creature, then return it to the battlefield tapped under its owner's control. ({C} represents colorless mana.)

Gigadrowse

Replicate {U} (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copies.)
Tap target permanent.

Court Street Denizen

Whenever another white creature you control enters, tap target creature an opponent controls.

Elite Scaleguard

When Elite Scaleguard enters, bolster 2. (Choose a creature with the least toughness among creatures you control and put two +1/+1 counters on it.)
Whenever a creature you control with a +1/+1 counter on it attacks, tap target creature defending player controls.