I posted a shitload of mechanic ideas in the Hearthstone thread. Wizards could never print these as they are ripped straight from the Blizzard game (abilities, names, cmc), but we could! Most of these are basic cards to showcase how I would word the ability in Magicese, so not all of them are cube-worthy, but I feel there might be a few nice keywords in here that would work well in cube.
Ironbeak Owl
Creature - Bird
When Ironbeak Owl enters the battlefield, silence target creature.
(That creature loses all abilities, then destroy all aura's attached to that creature.)
Druid of the Grove
Creature - Centaur Druid
When Druid of the Grove enters the battlefield, choose one - Silence target creature; or Druid of the Grove deals 2 damage to target creature or player.
2/4
Argent Squire
Creature - Human Soldier
Divine shield
(This creature enters the battlefield with a shield counter on it. The first time damage would be dealt to this creature each game, remove all shield counters from it instead.)
1/1
Argent Commander
Creature - Human Soldier
Divine shield, haste, provoke
4/2
Loot Hoarder
Creature - Human Wizard
Deathrattle - When Loot Hoarder dies, you may draw a card.
2/1
Haunted Creeper
Creature - Spider
Reach
Deathrattle - When Haunted Creeper dies, put two 1/1 black Spider creature tokens with reach onto the battlefield.
1/2
Worgen Infiltrator
Creature - Wolf Assassin
Stealth
(This creature has hexproof as long as it hasn't dealt combat damage this game.)
2/1
Windfury Harpy
Creature - Harpy Warrior
Windfury
(Whenever this creature attacks for the first time each turn, untap it. After this phase, there is an additional combat phase. This creature must attack in that combat phase, and no other creatures can attack in that combat phase.)
4/5
Amani Berserker
Creature - Troll Warrior
Enrage 3
(Damage isn't removed from this creature during the cleanup step. As long as it's damaged, it gets +3/+0.)
2/3
Raging Worgen
Creature - Wolf Warrior
Enrage 1
When this creature is damaged for the first time, untap it and it gains windfury.
3/3
I imagine weapons being implemented as equipment with power and durability counters (equal to value in toughness field). When a weapon enters the battlefield, sacrifice the currently armed weapon, then attach the new weapon to its controller when it enters the battlefield. A player can attack as though it were a creature with power equal to the Weapon's power while it is armed. Whenever a player attacks, remove a durability counter from the Weapon at end of combat. When a weapon has no durability counters remaining, sacrifice it.
Fiery Waraxe
Artifact - Weapon
(When this card enters the battlefield, destroy all other weapons you control. You can attack as though you were a creature with power equal to this card's power. If you do, remove a durability counter from it at end of combat.)
3/2
Hidden rules text:
- A weapon enters the battlefield with durability equal to its toughness;
- When a weapon has no durability counters on it, it is sacrificed as a state-based action;
- A weapon can't attack;
- If you are blocked while attacking, you take damage equal to the blocking creature's power.
SI-7 Agent
Creature - Human Assassin
Combo - When SI-7 Agent enters the battlefield, if you played another spell this turn, it deals 2 damage to target creature or player.
3/3
Lava Burst
Sorcery
Overload 2
(When this spell resolves, tap two lands you control. Those lands don't untap during your next untap step.)
Lava Burst deals 5 damage to target creature or player.
Fen Creeper
Creature - Plant Elemental
Taunt
(When this creature blocks, lethal damage must be assigned to it before damage can be assigned to creatures without taunt blocking the same creature.)
3/6