Guardian of Tazeem

Flying
Landfall — Whenever a land you control enters, tap target creature an opponent controls. If that land is an Island, that creature doesn't untap during its controller's next untap step.

Tsabo's Web

When this artifact enters, draw a card.
Each land with an activated ability that isn't a mana ability doesn't untap during its controller's untap step.

Quiet Contemplation

Whenever you cast a noncreature spell, you may pay {1}. If you do, tap target creature an opponent controls and it doesn't untap during its controller's next untap step.

An-Zerrin Ruins

As this enchantment enters, choose a creature type.
Creatures of the chosen type don't untap during their controllers' untap steps.

Crackdown

Nonwhite creatures with power 3 or greater don't untap during their controllers' untap steps.

Meekstone

Creatures with power 3 or greater don't untap during their controllers' untap steps.

Dungeon Geists

Flying
When this creature enters, tap target creature an opponent controls. That creature doesn't untap during its controller's untap step for as long as you control this creature.

Barl's Cage

{3}: Target creature doesn't untap during its controller's next untap step.

Somnophore

Flying
Whenever this creature deals damage to a player, tap target creature that player controls. That creature doesn't untap during its controller's untap step for as long as this creature remains on the battlefield.

Ice Floe

You may choose not to untap this land during your untap step.
{T}: Tap target creature without flying that's attacking you. It doesn't untap during its controller's untap step for as long as this land remains tapped.

Niblis of Frost

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever you cast an instant or sorcery spell, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.

Embargo

Nonland permanents don't untap during their controllers' untap steps.
At the beginning of your upkeep, you lose 2 life.

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.

Breaching Leviathan

When this creature enters, if you cast it from your hand, tap all nonblue creatures. Those creatures don't untap during their controllers' next untap steps.

Kill Switch

{2}, {T}: Tap all other artifacts. They don't untap during their controllers' untap steps for as long as this artifact remains tapped.

Time of Ice

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Tap target creature an opponent controls. It doesn't untap during its controller's untap step for as long as you control this Saga.
III — Return all tapped creatures to their owners' hands.

Lorthos, the Tidemaker

Whenever Lorthos attacks, you may pay {8}. If you do, tap up to eight target permanents. Those permanents don't untap during their controllers' next untap steps.

Matsu-Tribe Sniper

{T}: This creature deals 1 damage to target creature with flying.
Whenever this creature deals damage to a creature, tap that creature and it doesn't untap during its controller's next untap step.

Dream Tides

Creatures don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player may choose any number of tapped nongreen creatures they control and pay {2} for each creature chosen this way. If the player does, untap those creatures.

Dragon Turtle

Flash
Drag Below — When this creature enters, tap it and up to one target creature an opponent controls. They don't untap during their controllers' next untap steps.

Juntu Stakes

Creatures with power 1 or less don't untap during their controllers' untap steps.

Neko-Te

Whenever equipped creature deals damage to a creature, tap that creature. That creature doesn't untap during its controller's untap step for as long as this Equipment remains on the battlefield.
Whenever equipped creature deals damage to a player, that player loses 1 life.
Equip {2}

Energy Storm

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Prevent all damage that would be dealt by instant and sorcery spells.
Creatures with flying don't untap during their controllers' untap steps.

Thelon's Curse

Blue creatures don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player may choose any number of tapped blue creatures they control and pay {U} for each creature chosen this way. If the player does, untap those creatures.

Icy Blast

Tap X target creatures.
Ferocious — If you control a creature with power 4 or greater, those creatures don't untap during their controllers' next untap steps.

Marble Titan

Shield of the Righteous

Equipped creature gets +0/+2 and has vigilance.
Whenever equipped creature blocks a creature, that creature doesn't untap during its controller's next untap step.
Equip {2}

Tangle

Prevent all combat damage that would be dealt this turn.
Each attacking creature doesn't untap during its controller's next untap step.

Kiora Bests the Sea God

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Create an 8/8 blue Kraken creature token with hexproof.
II — Tap all nonland permanents target opponent controls. They don't untap during their controller's next untap step.
III — Gain control of target permanent an opponent controls. Untap it.

Ojutai, Soul of Winter

Flying, vigilance
Whenever a Dragon you control attacks, tap target nonland permanent an opponent controls. That permanent doesn't untap during its controller's next untap step.

Mist of Stagnation

Permanents don't untap during their controllers' untap steps.
At the beginning of each player's upkeep, that player chooses a permanent for each card in their graveyard, then untaps those permanents.

Sharktocrab

{2}{G}{U}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on this creature, tap target creature an opponent controls. That creature doesn't untap during its controller's next untap step.