Just freeze mage, for those who knows it.
vs aggro decks: you want a defensive card like one Frostbolt or Doomsayer. Then ideally 2 draw minions such as Arcanologist or Loot Hoarder, to fight there 2 drop. Turn 5 is typically you want to Frost Nova + Doomsayer.
vs midrange decks: Keep draw minions like Arcanologist, Loot Hoarder, Novice Engineer. Arcane Intellect and Acolyte of Pain are also great here. Draw early so u can optimize later plays. Freeze spell get the best value later in the game.
vs ctr decks: We mainly want many cards to draw. We don't have to fear that our opponent pushing us so leaving Doomsayer /aoe or some burst card isn't needed.