Aven Riftwatcher

Flying
Vanishing 3 (This creature enters with three time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When this creature enters or leaves the battlefield, you gain 2 life.

Saproling

Pallid Mycoderm

At the beginning of your upkeep, put a spore counter on this creature.
Remove three spore counters from this creature: Create a 1/1 green Saproling creature token.
Sacrifice a Saproling: Each creature you control that's a Fungus or a Saproling gets +1/+1 until end of turn.

Fury Charm

Choose one —
• Destroy target artifact.
• Target creature gets +1/+1 and gains trample until end of turn.
• Remove two time counters from target permanent or suspended card.

Hammerheim Deadeye

Echo {5}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, destroy target creature with flying.

Keldon Marauders

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
When this creature enters or leaves the battlefield, it deals 1 damage to target player or planeswalker.

Lavacore Elemental

Vanishing 1 (This creature enters with a time counter on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a creature you control deals combat damage to a player, put a time counter on this creature.

Magus of the 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.)

Needlepeak Spider

Shivan Meteor

Shivan Meteor deals 13 damage to target creature.
Suspend 2—{1}{R}{R} (Rather than cast this card from your hand, you may pay {1}{R}{R} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Stingscourger

Echo {3}{R} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, return target creature an opponent controls to its owner's hand.

Sulfur Elemental

Flash
Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
White creatures get +1/-1.

Timecrafting

Choose one —
• Remove X time counters from target permanent or suspended card.
• Put X time counters on target permanent with a time counter on it or suspended card.

Poultice Sliver

All Slivers have "{2}, {T}: Regenerate target Sliver." (The next time that Sliver would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)

Torchling

{R}: Untap this creature.
{R}: Target creature blocks this creature this turn if able.
{R}: Change the target of target spell that targets only this creature.
{1}: This creature gets +1/-1 until end of turn.
{1}: This creature gets -1/+1 until end of turn.

Volcano Hellion

This creature has echo {X}, where X is your life total. (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, it deals an amount of damage of your choice to you and target creature. The damage can't be prevented.

Boom

Destroy target land you control and target land you don't control.

Planar Chaos