Spell Syphon

Counter target spell unless its controller pays {1} for each blue permanent you control.

Unwilling Recruit

Gain control of target creature until end of turn. Untap that creature. It gets +X/+0 and gains haste until end of turn.

Riverfall Mimic

Whenever you cast a spell that's both blue and red, Riverfall Mimic has base power and toughness 3/3 until end of turn and can't be blocked this turn.

Hatchet Bully

{2}{R}, {T}, Put a -1/-1 counter on a creature you control: Hatchet Bully deals 2 damage to any target.

Noggle Bandit

Noggle Bandit can't be blocked except by creatures with defender.

Jaws of Stone

Jaws of Stone deals X damage divided as you choose among any number of targets, where X is the number of Mountains you control as you cast this spell.

Oona's Grace

Target player draws a card.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Clout of the Dominus

Enchant creature
As long as enchanted creature is blue, it gets +1/+1 and has shroud. (It can't be the target of spells or abilities.)
As long as enchanted creature is red, it gets +1/+1 and has haste.

Crag Puca

{U/R}: Switch Crag Puca's power and toughness until end of turn.

Island

Noggle Hedge-Mage

When Noggle Hedge-Mage enters, if you control two or more Islands, you may tap two target permanents.
When Noggle Hedge-Mage enters, if you control two or more Mountains, you may have Noggle Hedge-Mage deal 2 damage to target player or planeswalker.

Mountain

Burn Trail

Burn Trail deals 3 damage to any target.
Conspire (As you cast this spell, you may tap two untapped creatures you control that share a color with it. When you do, copy it and you may choose a new target for the copy.)

Noggle Bridgebreaker

When Noggle Bridgebreaker enters, return a land you control to its owner's hand.

Flame Jab

Flame Jab deals 1 damage to any target.
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

Merrow Levitator

{T}: Target creature gains flying until end of turn.
Whenever you cast a blue spell, you may untap Merrow Levitator.

Shrewd Hatchling

Shrewd Hatchling enters with four -1/-1 counters on it.
{U/R}: Target creature can't block Shrewd Hatchling this turn.
Whenever you cast a blue spell, remove a -1/-1 counter from Shrewd Hatchling.
Whenever you cast a red spell, remove a -1/-1 counter from Shrewd Hatchling.

Dominus of Fealty

Flying
At the beginning of your upkeep, you may gain control of target permanent until end of turn. If you do, untap it and it gains haste until end of turn.

Inside Out

Switch target creature's power and toughness until end of turn.
Draw a card.

Nucklavee

When Nucklavee enters, you may return target red sorcery card from your graveyard to your hand.
When Nucklavee enters, you may return target blue instant card from your graveyard to your hand.

Outrage Shaman

Chroma — When Outrage Shaman enters, it deals damage to target creature equal to the number of red mana symbols in the mana costs of permanents you control.

Stream Hopper

{U/R}: Stream Hopper gains flying until end of turn.

Mindwrack Liege

Other blue creatures you control get +1/+1.
Other red creatures you control get +1/+1.
{U/R}{U/R}{U/R}{U/R}: You may put a blue or red creature card from your hand onto the battlefield.