Evil Eye of Orms-by-Gore

Non-Eye creatures you control can't attack.
Evil Eye of Orms-by-Gore can't be blocked except by Walls.

Ovinomancer

When Ovinomancer enters, sacrifice it unless you return three basic lands you control to their owner's hand.
{T}, Return Ovinomancer to its owner's hand: Destroy target creature. It can't be regenerated. That creature's controller creates a 0/1 green Sheep creature token.

Arena

{3}, {T}: Tap target creature you control and target creature of an opponent's choice they control. Those creatures fight each other. (Each deals damage equal to its power to the other.)

Giant Oyster

You may choose not to untap Giant Oyster during your untap step.
{T}: For as long as Giant Oyster remains tapped, target tapped creature doesn't untap during its controller's untap step, and at the beginning of each of your draw steps, put a -1/-1 counter on that creature. When Giant Oyster leaves the battlefield or becomes untapped, remove all -1/-1 counters from the creature.

Eron the Relentless

Haste
{R}{R}{R}: Regenerate Eron the Relentless.

Stupor

Target opponent discards a card at random, then discards a card.

Uthden Troll

Dandân

Dandân can't attack unless defending player controls an Island.
When you control no Islands, sacrifice Dandân.

Sindbad

{T}: Draw a card and reveal it. If it isn't a land card, discard it.

Orcish Librarian

{R}, {T}: Look at the top eight cards of your library. Exile four of them at random, then put the rest on top of your library in any order.

Butcher Orgg

You may assign Butcher Orgg's combat damage divided as you choose among defending player and/or any number of creatures they control.

Shadow Guildmage

{U}, {T}: Put target creature you control on top of its owner's library.
{R}, {T}: Shadow Guildmage deals 1 damage to any target and 1 damage to you.

Conspiracy

As Conspiracy enters, choose a creature type.
Creatures you control are the chosen type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Uncle Istvan

Prevent all damage that would be dealt to Uncle Istvan by creatures.

Fire Whip

Enchant creature you control
Enchanted creature has "{T}: This creature deals 1 damage to any target."
Sacrifice Fire Whip: Fire Whip deals 1 damage to any target.

Mistform Ultimus

Mistform Ultimus is every creature type (even if this card isn't on the battlefield).

Nicol Bolas, Dragon-God

Nicol Bolas, Dragon-God has all loyalty abilities of all other planeswalkers on the battlefield.
+1: You draw a card. Each opponent exiles a card from their hand or a permanent they control.
−3: Destroy target creature or planeswalker.
−8: Each opponent who doesn't control a legendary creature or planeswalker loses the game.

Sol'kanar the Swamp King

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Whenever a player casts a black spell, you gain 1 life.

Soul Collector

Flying
Whenever a creature dealt damage by Soul Collector this turn dies, return that card to the battlefield under your control.
Morph {B}{B}{B} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Dodecapod

If a spell or ability an opponent controls causes you to discard Dodecapod, put it onto the battlefield with two +1/+1 counters on it instead of putting it into your graveyard.

Grinning Totem

{2}, {T}, Sacrifice Grinning Totem: Search target opponent's library for a card and exile it. Then that player shuffles. Until the beginning of your next upkeep, you may play that card. At the beginning of your next upkeep, if you haven't played it, put it into its owner's graveyard.

Kobold Taskmaster

Other Kobold creatures you control get +1/+0.

Darkness

Prevent all combat damage that would be dealt this turn.

Feldon's Cane

{T}, Exile Feldon's Cane: Shuffle your graveyard into your library.

Merfolk Assassin

{T}: Destroy target creature with islandwalk.

Flying Men

Pirate Ship

Pirate Ship can't attack unless defending player controls an Island.
{T}: Pirate Ship deals 1 damage to any target.
When you control no Islands, sacrifice Pirate Ship.

Undertaker

{B}, {T}, Discard a card: Return target creature card from your graveyard to your hand.

Funeral Charm

Choose one —
• Target player discards a card.
• Target creature gets +2/-1 until end of turn.
• Target creature gains swampwalk until end of turn. (It can't be blocked as long as defending player controls a Swamp.)

Safe Haven

{2}, {T}: Exile target creature you control.
At the beginning of your upkeep, you may sacrifice Safe Haven. If you do, return each card exiled with Safe Haven to the battlefield under its owner's control.

Snow-Covered Swamp

Swamp Mosquito

Flying
Whenever Swamp Mosquito attacks and isn't blocked, defending player gets a poison counter. (A player with ten or more poison counters loses the game.)

Suq'Ata Lancer

Haste
Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)

Claws of Gix

{1}, Sacrifice a permanent: You gain 1 life.

Island

Stormscape Familiar

Flying
White spells and black spells you cast cost {1} less to cast.

War Barge

{3}: Target creature gains islandwalk until end of turn. When War Barge leaves the battlefield this turn, destroy that creature. A creature destroyed this way can't be regenerated. (A creature with islandwalk can't be blocked as long as defending player controls an Island.)

Mountain

Leviathan

Trample
Leviathan enters tapped and doesn't untap during your untap step.
At the beginning of your upkeep, you may sacrifice two Islands. If you do, untap Leviathan.
Leviathan can't attack unless you sacrifice two Islands. (This cost is paid as attackers are declared.)