Beat the Clock -- 2WU
Enchantment (R)
Beat the Clock enters the battlefield with five time counters on it.
At the beginning of each upkeep, remove a time counter from Beat the Clock. When the last time counter is removed, the player with the highest life total wins the game. If two or more players are tied for highest life total, the game is a draw.
Speartooth Moloch -- 2WW
Creature -- Lizard (R)
First Strike
When Speartooth Moloch dies, create two Equipment artifact tokens named Moloch's Tooth with Equip 2 and "Equipped creature gets +2/+0 and has first strike."
4/2
Soul of Dominaria -- 4WW
Creature -- Avatar
Lifelink 3WW: Create three 1/1 white Soldier creature tokens, then you gain 1 life for each creature you control. 3WW, Exile Soul of Dominaria from your graveyard: Create three 1/1 white Soldier creature tokens, then you gain 1 life for each creature you control.
6/6
Next: Any of the Shadowmoor ally-colored Spirit Avatars (Demigod of Revenge, et al) in their colors' shared enemy color (So Demigod of Revenge in W, etc.)
Darksteel Chimera -- 4
Artifact
Indestructible XX: Darksteel Chimera becomes an X/X Construct artifact creature until end of turn.
As long as Darksteel Chimera is a creature, artifact creatures you control get +X/+X, where X is Darksteel Chimera's power.
Abzan Vitalmage -- 3G
Creature -- Human Shaman
If one or more counters would be placed on a creature you control, you may place that many counters plus one on that creature instead. 3G, T: Bolster 1.
2/2
Sensei's Apprentice -- WU
Creature -- Human Wizard (U)
Whenever you draw a card, you gain 1 life. 3, T: Scry 3. "I realized his top was not a toy when it predicted to the second which way the wind would shift during a sparring session." --Akima, Apprentice of Sensei Golden-Tail
2/2
Leyline Warrior -- 2G
Creature -- Elf Warrior (U)
Leyline Warrior gets +1/+1 for each type of mana that's been added to your mana pool this turn. (The types of mana are white, blue, black, red, green, and colorless.)
2/2
Pristine Quarry
Land (R)
At the beginning of each opponent's end step, if no creatures that player controls attacked you or a planeswalker you control this turn, put a charge counter on Pristine Quarry. T, Remove a charge counter from Pristine Quarry: Add one mana of any color to your mana pool.
Alabaster Prison -- XWW
Enchantment (R)
Alabaster Prison enters the battlefield with X chain counters on it.
Creatures can't attack you or planeswalkers you control unless their controller pays 1 for each chain counter on Alabaster Prison for each creature he or she controls that's attacking you.
Flow of Ingenuity -- 2UU
Enchantment (U)
Whenever an artifact enters the battlefield under your control, you may add C to your mana pool. The more a true master works, the more her ideas seem to flow one from another.
Votes for BlackTempleGuardian (Though the ability might need to be tinkered with to work properly) and Indighost.
Burbling Totemspeaker -- 2B
Creature -- Human Shaman (C)
When Burbling Totemspeaker enters the battlefield, create a Totem artifact token. 2B, T, Sacrifice Burbling Totemspeaker: Target creature gets -X/-X until end of turn, where X is the number of Totems you control.
1/2
Votes for Rudyard and netn10 (though, as a one-shot Counterbalance, I'd think UU would be the more appropriate cost.)
Magma Totemspeaker -- 3RR
Creature -- Lizard Shaman (U)
When Magma Totemspeaker enters the battlefield, create a Totem artifact token.
Totems you control have "R, T: This artifact deals 1 damage to target creature."
2/2
Beat the Clock -- 2WU
Enchantment (R)
Beat the Clock enters the battlefield with five time counters on it.
At the beginning of each upkeep, remove a time counter from Beat the Clock. When the last time counter is removed, the player with the highest life total wins the game. If two or more players are tied for highest life total, the game is a draw.
Speartooth Moloch -- 2WW
Creature -- Lizard (R)
First Strike
When Speartooth Moloch dies, create two Equipment artifact tokens named Moloch's Tooth with Equip 2 and "Equipped creature gets +2/+0 and has first strike."
4/2
Soul of Dominaria -- 4WW
Creature -- Avatar
Lifelink
3WW: Create three 1/1 white Soldier creature tokens, then you gain 1 life for each creature you control.
3WW, Exile Soul of Dominaria from your graveyard: Create three 1/1 white Soldier creature tokens, then you gain 1 life for each creature you control.
6/6
Next: Any of the Shadowmoor ally-colored Spirit Avatars (Demigod of Revenge, et al) in their colors' shared enemy color (So Demigod of Revenge in W, etc.)
Artifact
Indestructible
XX: Darksteel Chimera becomes an X/X Construct artifact creature until end of turn.
As long as Darksteel Chimera is a creature, artifact creatures you control get +X/+X, where X is Darksteel Chimera's power.
Next: Ib Halfheart, Goblin Tactician
Creature -- Human Shaman
If one or more counters would be placed on a creature you control, you may place that many counters plus one on that creature instead.
3G, T: Bolster 1.
2/2
Next: Thassa, God of the Sea
Infiltrator's Insight -- 2UB
Enchantment (R)
If you would scry X, you may pay 1 life and scry X + 1 instead.
1UB, pay 1 life: Draw a card.
Sensei's Apprentice -- WU
Creature -- Human Wizard (U)
Whenever you draw a card, you gain 1 life.
3, T: Scry 3.
"I realized his top was not a toy when it predicted to the second which way the wind would shift during a sparring session." --Akima, Apprentice of Sensei Golden-Tail
2/2
Ugin's Prism -- 2
Artifact (C)
When Ugin's Prism enters the battlefield, draw a card.
C, T: Add one mana of any color to your mana pool.
Leyline Warrior -- 2G
Creature -- Elf Warrior (U)
Leyline Warrior gets +1/+1 for each type of mana that's been added to your mana pool this turn. (The types of mana are white, blue, black, red, green, and colorless.)
2/2
Pristine Quarry
Land (R)
At the beginning of each opponent's end step, if no creatures that player controls attacked you or a planeswalker you control this turn, put a charge counter on Pristine Quarry.
T, Remove a charge counter from Pristine Quarry: Add one mana of any color to your mana pool.
Alabaster Prison -- XWW
Enchantment (R)
Alabaster Prison enters the battlefield with X chain counters on it.
Creatures can't attack you or planeswalkers you control unless their controller pays 1 for each chain counter on Alabaster Prison for each creature he or she controls that's attacking you.
Flow of Ingenuity -- 2UU
Enchantment (U)
Whenever an artifact enters the battlefield under your control, you may add C to your mana pool.
The more a true master works, the more her ideas seem to flow one from another.
Burbling Totemspeaker -- 2B
Creature -- Human Shaman (C)
When Burbling Totemspeaker enters the battlefield, create a Totem artifact token.
2B, T, Sacrifice Burbling Totemspeaker: Target creature gets -X/-X until end of turn, where X is the number of Totems you control.
1/2
Magma Totemspeaker -- 3RR
Creature -- Lizard Shaman (U)
When Magma Totemspeaker enters the battlefield, create a Totem artifact token.
Totems you control have "R, T: This artifact deals 1 damage to target creature."
2/2
Jungle Totemspeaker -- 2GG
Creature -- Beast Shaman (U)
Trample
When Jungle Totemspeaker enters the battlefield, create a Totem artifact token.
Jungle Totemspeaker gets +1/+1 for each Totem you control.
3/3