Mark Rosewater's hints.
• a five-color legendary enchantment
• 2{B} for a 6/6 with deathtouch
• a card that allows you to kill someone with poison
• A card with a {W}{W}{U}{U}{B}{B}{R}{R}{G}{G},{T} activation
• a card that lets you use a creature’s toughness to perform an action normally using a creature’s power
• numerous new noncreature tokens
• a card that can make a token that’s a copy of target permanent for no mana
• a black creature that can copy other creatures
• the introduction of a creature type that players have been wanting for years
• a card with three activation costs, one that’s only ever used once before and the other two have never been used before
• “protection from God creatures”
• “Sacrifice five Treasures:”
• “if three or more creatures died this turn”
• “Choose 1, 2, or 3 at random.”
• “except for Giants, Wizards, and lands”
• “you may search your library and/or graveyard for a Rune card”
• “As long as you control three or more legendary creatures”
• “X is the number of Vehicles you control plus the number of Equipment you control”
• “As long as you have at least 7 life more than your starting life total”
• “create X of those tokens instead”
• Angel Warrior
• Zombie Rogue
• Dwarf Cleric
• Horse Spirit
• Vampire Dragon
• Legendary Creature – Wolf
• Legendary Creature – Bird Spirit
• Legendary Creature – Giant Wizard
• Legendary Creature – Demon Berserker
• Legendary Creature – Squirrel