They updated their Facebook album with all the cards shown so far (37 cards). Looking through them, there's a lot of 'random', but nothing that's super unplayable or broken. I'm excited for next month.
There are 7 Spare Part cards (+1 hp, freeze, 1 turn stealth, hp/atk swap, taunt, friendly minion return, +1 hp). I love me some Crazed Alchemist, and getting that effect could swing a game. And really +1 hp/atk seems to me to be the weakest of those Spare Part cards, but they're not terrible. But you really can't plan to get a specific Spare Part considering there are 7 of them.
Enhance-o Mechano seems super strong in zoo as a 4/3/2 that gives all your other minions either windfury, taunt, or divine shield.
Shrinkmeister is a priest only 2/3/2 that reduces atk by 2, good for SW
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Gnomish Experimenter is a 3/3/2 with battlecry: draw a card, if it's a minion, turn it into a chicken. It's a pretty high risk card, but could work in a spell heavy deck. I don't really hate it, but I'd be terrified to play it.