***TRIALS RESPONSE***This is indeed an interesting and good idea, as Voodoo Dolls synergizes pretty well with Overdrives and Rage Pots. I am a bit afraid that all of the well-synergizing cards w/ Voodoo Dolls may be a tad bit too hard to put in a stabile deck. So I'd cut it down to a duo. So the main question will be: Will you go fire/darkness, or will you choose gravity/darkness?
Going with gravity/darkness, the main combo will be Overdrive + Voodoo Doll. You could for example add Otyughs if you like having CC, you could even add a Trebuchet or two if you'd like (I'm not saying it's a good idea ). IMO a few Liquid Shadows will improve this deck, as while their HP goes down, your opponent gets poison counters, that counters (no pun intended) shields and stuff while your opponent's HP is depleting. If I was to make the deck I would make it something like this:
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74b 74i 74i 74i 74i 74i 7t8 7t8 7t9 7t9 7te 7te 7te 7tg 7tg 7tg 7tg 7tg 7tg 7um 7um 7um 7um 7um 7um 7um 7um 7um 7um 7um 8pl
Then we can go fire/darkness. While Gravity is better while time goes, fire is better at quick damage. The Elixirs can make some pretty hard hitting dolls. You can add some low-cost Explosions, a Rain of Fire or two to eliminate oppositing critters, or maybe a few Minor Phoenixes to add some extra damage. The variations is endless. Here are my take on that deck:
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7dm 7dm 7dm 7do 7do 7dr 7dr 7dr 7dr 7dr 7dr 7tb 7tb 7tg 7tg 7tg 7tg 7tg 7tg 7um 7um 7um 7um 7um 7um 7um 7um 7um 7um 7um 8po
[/list]As I've said before, my decks are not the best aviable. Tweak it any way you want to - there are a lot of cards that can be added to improve the deck.
Have fun