some cards i could see to combo with shiftry are...
Claydol (HP), Glalie (EM), Gyarados (DX), heck with all the delta species going around maybe even Lickitung (DF), another options is Luvdisc (CG) but they need to have a stadium in play, Manectric (EM) but this one takes a little more time to power up then the others, Nosepass (EM), Rayquaza Ex D, (DF), Umbreon (DS) if they attach a special enegy, yeah damage then snipe another, Weezing (DS) targets bodies.
Yeah, that's about it. The idea is to just spread minum damage with your "starter". Then comes shiftry. I kind of like Weezing in this. Shiftry targets Powers and Weezing targets Bodies. Weezing is weak to psychic, shiftry has resistant to psychic. And with cursed stone the damage just starts to add up on those powers.
I mean you could try Jolteon Ex, and still play Cursed Stone as you would want to play 4 ssu. Once 1 of those hits head, the damage is removed. Delta could really hurt you, as those zzapps and split bombs add up fast.