Merlin, Rabbit is the only card that allows you to draw, and while Tiana, Celebrating Princess does provide some benefit to an empty hand, the problem is that every card you draw of the top will cost less than four ink and be fairly low impact
If the creature can't attack any of those players but could otherwise attack, it must attack a planeswalker an opponent controls, a battle an opponent protects, or the player that goaded it
"Can't Hold It Back Anymore" includes artwork that immediately gives an epic feeling of power and royalty, befitting the ice queen, and matching the powerful ability that the card gives players to exert and damage a character
In deck building, this balance is called the "mana curve." Each spell has a mana value, which is the total mana cost of a spell