When I was doing the Curse of Naxxramas expansion, it seemed like the mage card Duplicate was a pretty powerful card. I don’t really like secrets all that much, but this one was special. At the time, I only rolled with Mirror Entity in my mage deck. When I unlocked Duplicate, I immediately put it into my deck, no questions asked.
Later on when I got the Mad scientist, it made even more sense, there was synergy. Even without the synergy, I think the Duplicate card stands on it’s own. I can’t imagine playing a mage deck without it.
I tend to go for cards with some versatility to them. Kill Command for a hunter, for instance. It does 3 damage to a character, 5 damage if you have a beast on the board. There are a handful of cards like this throughout the classes.
Druids are a class full of versatility. From Druid of the Claw to Nourish. Swipe is also a really great card. Since it’s a spell, it can be pumped up by minions who boost your spell power. A sneaky good card for this is the Azure Drake. For 5 mana you get a 4/4 minion that gives you +1 spell power and a Battlecry: draw a card. A lot of bang for your buck there.
So what is a ‘must have’ in your decks? Feel free to let me know in the comments down under!