Giggling Drunkard
Creature - Human Rogue
If this would deal combat damage to a player, gain 4 life instead.
Jolly (If this creature is blocking or blocked by a creature, remove this creature and those creatures from combat.)
1/2
Wine is a mocker, the wined are a laughter.

Burden of Proof -
Instant
Kicker - Counter another spell you control.
Tap target creature. If Burden of Proof was kicked, put that creature on top of its owner's library instead.

Eager Student
Creature - Human Wizard (C)
Learn (Whenever you cast a noncreature spell, if its converted mana cost is greater than this creature's power, put a +1/+1 counter on this creature.)
"Welcome to the academy! Let's begin our first topic: divination."
-Yehan, academy instructor
2/2

I Learn.

Opportunistic Burglar

Creature -- Human Rogue (U)
Malleable (Whenever this creature attacks or blocks, you may switch its power and toughness until end of turn.)
Whenever Opportunistic Burglar deals exactly 1 combat damage to a player, draw a card.
3/1

Still No -
Instant
No. (You can't. Creatures do not. Opponents cannot. Activated abilities do not. Permanents can't. Your mana pool doesn't. Spells don't.)

Thanks!

Armory Burglar
Creature - Human Rogue (U)
Opportunist (This creature can't be blocked unless it's the only creature blocked this combat.)
Whenever Armory Burglar deals combat damage to an opponent, put a +1/+1 counter on it.
1/1

Magic probably has enough evasion keywords already, but they're so easy to come up with!

Hidden Slingshooter
Creature - Goblin Pest (U)
Menace, patience (You may choose not to untap this during your untap step.)
Whenever Hidden Slingshooter untaps, it deals 1 damage to target creature.
Grok could do few things well. But he sure could wait.
1/1

Bitchy Ex
Creature - Human Warrior (U)
Menace
Quarrel - When this creature enters the battlefield, it fights target creature.
4/1

Ability word so it can be changed to other types for design purposes (targets flying creatures, targets artifact creatures, etc...) Not sure I did that correctly though. Maybe Quarrel - Flying?

Murder of Ravens
Creature - Bird (C)
Flying
Quarrel - When this creature enters the battlefield, it fights target creature with flying.
2/2

Luddite Mob
Creature - Human Warrior (U)
Whenever an artifact is destroyed, put a +1/+1 counter on Luddite Mob.
Quarrel - When this creature enters the battlefield, it fights target artifact creature.
4/4

Ash of the Withering Flame
Enchantment - Aura
Enchant Creature
At the end of your turn, put a -1/-1 counter on enchanted creature.
Radioactive (As long as this card is in your graveyard and there are more cards with radioactive in your graveyard than there are cards without radioactive, at the beginning of your precombat main phase, lose 1 life and add to your mana pool.)

Shrieking Horror
Creature - Horror (U)
Screech (Whenever this creature attacks, each creature defending player controls gets -1/-0 until end of turn.)
Shrieking Horror has haste as long as an opponent controls three or more creatures.
"Its a truly terrifying sound, it is. Echoes in your head for days."
-Gregon, Greatden paladin
4/1

Cloven Lightning
Sorcery
As you cast ~, you may tear it. (Copy this spell. You may choose new targets for the copy.
~ deals 4 damage to target creature. If ~ was torn or a copy, it deals 2 damage instead.

Might of the Roots
Instant (U)
Target creature gets +2/+2 and gains trample until end of turn.
Uproot -2 (, Discard this card: Target land becomes a 2/2 Elemental creature indefinitely.)
When Might of the Roots uproots a land, that land gains trample indefinitely.

Honored Gargantuan

Creature -- Beast (C)
Venerate (Whenever a creature with lesser power enters the battlefield under your control, put a +1/+1 counter on this.)
"Your gods are distant and inscrutable. Ours make their wishes quite clear." —Nati, Godspeaker of Naya
4/4

Shears of Fate
Instant
Name a creature card. Whenever a named creature enters the battlefield this turn, destroy it.
Weave (Whenever a player plays a card, you pay this card's weave cost. If you do, reveal it and cast a copy of this card.)

Buried Secrets

Instant (U)
Draw two cards.
X Marks the Spot (Shuffle this into its owner's library after it resolves. The next time you draw a card with the same name as this spell, you may reveal it and cast it without paying its mana cost.)

Roaring Kavu
Creature - Kavu (C)
Yavimayan (When this creature enters the battlefield, all creatures get +1/+1 until end of turn.)
4/3

Y is a hard letter.

Scaredy Cat
Creature - Cat
Whenever Scaredy Cat enters the battlefield, scry 2.
Zoinks (Whenever a creature with power greater than this creature's power enters the battlefield, you may return this creature to your hand.)
1/3

Ambuscade Knight

Creature -- Human Knight (U)
First strike
Ambush (At the beginning of your upkeep, you may exile this card from your hand face down. As long as it remains in exile, you may look at it and cast it as though it had Flash.)
2/2

Grandmaster's Emissary -
Creature - Fox Samurai
Bushido - Double strike and lifelink. (Whenever Grandmaster's Emissary blocks or becomes blocked, it gets double strike and lifelink until end of turn.)
2/2

Ethercaste Slayer
Artifact Creature - Human Knight (U)
Flash
Comeback (When this creature enters the battlefield, if you have 10 or less life, you gain 2 life and draw a card.)
"These monsters fight like nothing we've ever seen. Maybe we need to do the same."
2/3