Always Crystology - thins the deck by drawing either good early defensive options (Righteous Protectors) or more card draw (Novice Engineers); it's also a completely dead card late-game unless you need to hold onto something to trigger a potential Counterspell.
Depends on which type of aggro somewhat but for things like Zoolock then Righteous Protectors and Equality are good, Keep Pyromancer if you've already got Equality. Consecration can be good against Zoolock or other Paladins and Truesilver Champion is useful against Heal-Zoolock.
Don't underestimate a simple 4 life gain and cycling with Flash of Light either.
Try to stay alive whilst cycling through your deck as fast as possible, chipping away at your opponent’s health when you can.
Play Shirvallah, use Baleful Banker to add a copy to your deck then draw it with Holy Wrath, dealing 25 damage to your opponent’s face – if you’ve still got a charge left on Uther’s Lifesteal sword that’s another 5 damage bringing the total to 30 and OTK … taunt/armour notwithstanding. 25 damage is usually enough though.