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.

Avalanche Riders

Haste
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 Avalanche Riders enters, destroy target land.

Icatian Javelineers

Icatian Javelineers enters with a javelin counter on it.
{T}, Remove a javelin counter from Icatian Javelineers: It deals 1 damage to any target.

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 Aven Riftwatcher enters or leaves the battlefield, you gain 2 life.

Plains

Children of Korlis

Sacrifice Children of Korlis: You gain life equal to the life you've lost this turn. (Damage causes loss of life.)

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Mountain

Dust Elemental

Flash (You may cast this spell any time you could cast an instant.)
Flying; fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
When Dust Elemental enters, return three creatures you control to their owner's hand.

Gone

Return target creature you don't control to its owner's hand.

Dead

Dead // Gone

Stonecloaker

Flash
Flying
When Stonecloaker enters, return a creature you control to its owner's hand.
When Stonecloaker enters, exile target card from a graveyard.

Jhoira's Timebug

{T}: Choose target permanent you control or suspended card you own. If that permanent or card has a time counter on it, you may remove a time counter from it or put another time counter on it.

Errant Doomsayers

{T}: Tap target creature with toughness 2 or less.

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 Keldon Marauders enters or leaves the battlefield, it deals 1 damage to target player or planeswalker.

Brute Force

Target creature gets +3/+3 until end of turn.

Riftmarked Knight

Protection from black; flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
Suspend 3—{1}{W}{W}
When the last time counter is removed from Riftmarked Knight while it's exiled, create a 2/2 black Knight creature token with flanking, protection from white, and haste.

Sunlance

Sunlance deals 3 damage to target nonwhite creature.

Dawn Charm

Choose one —
• Prevent all combat damage that would be dealt this turn.
• Regenerate target creature.
• Counter target spell that targets you.

Stormfront Riders

Flying
When Stormfront Riders enters, return two creatures you control to their owner's hand.
Whenever Stormfront Riders or another creature is returned to your hand from the battlefield, create a 1/1 white Soldier creature token.

Fatal Frenzy

Until end of turn, target creature you control gains trample and gets +X/+0, where X is its power. Sacrifice it at the beginning of the next end step.

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 Lavacore Elemental.

Soltari Priest

Protection from red
Shadow (This creature can block or be blocked by only creatures with shadow.)

Whitemane Lion

Flash
When Whitemane Lion enters, return a creature you control to its owner's hand.

Calciderm

Shroud (This creature can't be the target of spells or abilities.)
Vanishing 4 (This creature enters with four time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)

Mogg War Marshal

Echo {1}{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 Mogg War Marshal enters or dies, create a 1/1 red Goblin creature token.