Twinspell Freeze a minion. If it's already Frozen, deal 2 damage to it.
If you have zero chill, this can help.
Freeze - Frozen characters lose their next attack.
Twinspell - Can be cast twice.
Ray of Frost
This card is just straight up good. In any sort of Mage that runs freeze like Exodia or Mill, being able to freeze 2 big minions on your opponents board for 2 mana (or even better, their 1 big minion for 1 mana) is perfect stall.