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.
Key play: If we can afford it, it is best to throw the Arcanologist before of Loot Hoarder, Novice Engineer and other draw cards. Because we want to have some value with the Arcanologist so that only those cards draw us secrets and not the other cards.