Mundungu

{T}: Counter target spell unless its controller pays {1} and 1 life.

Desecration Demon

Flying
At the beginning of each combat, any opponent may sacrifice a creature of their choice. If a player does, tap this creature and put a +1/+1 counter on it.

Power Leak

Enchant enchantment
At the beginning of the upkeep of enchanted enchantment's controller, that player may pay any amount of mana. This Aura deals 2 damage to that player. Prevent X of that damage, where X is the amount of mana that player paid this way.

Aether Storm

Creature spells can't be cast.
Pay 4 life: Destroy Aether Storm. It can't be regenerated. Any player may activate this ability.

Lim-Dûl's Hex

At the beginning of your upkeep, for each player, this enchantment deals 1 damage to that player unless they pay {B} or {3}.

Death Charmer

Whenever this creature deals combat damage to a creature, that creature's controller loses 2 life unless they pay {2}.

Island

Errant Minion

Enchant creature
At the beginning of the upkeep of enchanted creature's controller, that player may pay any amount of mana. This Aura deals 2 damage to that player. Prevent X of that damage, where X is the amount of mana that player paid this way.

Meddle

If target spell has only one target and that target is a creature, change that spell's target to another creature.

Psychic Puppetry

You may tap or untap target permanent.
Splice onto Arcane {U} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Disruptive Student

{T}: Counter target spell unless its controller pays {1}.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Soothsaying

{3}{U}{U}: Shuffle your library.
{X}: Look at the top X cards of your library, then put them back in any order.

Swamp

Condescend

Counter target spell unless its controller pays {X}. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Mana Leak

Counter target spell unless its controller pays {3}.

Flay

Target player discards a card at random. Then that player discards another card at random unless they pay {1}.

Essence Leak

Enchant permanent
As long as enchanted permanent is red or green, it has "At the beginning of your upkeep, sacrifice this permanent unless you pay its mana cost."

Immobilizing Ink

Enchant creature
Enchanted creature doesn't untap during its controller's untap step.
Enchanted creature has "{1}, Discard a card: Untap this creature."

Tidal Flats

{U}{U}: For each attacking creature without flying, its controller may pay {1}. If that player doesn't, creatures you control blocking that creature gain first strike until end of turn.

Freed from the Real

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

Ribbon Snake

Flying
{2}: This creature loses flying until end of turn. Any player may activate this ability.

Fade Away

For each creature, its controller sacrifices a permanent of their choice unless they pay {1}.

Elixir of Immortality

{2}, {T}: You gain 5 life. Shuffle this artifact and your graveyard into their owner's library.