So here is my idea, I know Mewtwo EX is going to be almost impossible to get unless you have a lot of money and can buy it off eBay. But I would like to try out Regigigas. He has a lot of HP, he can hit pretty hard and with an eviolite, even Donphan's 2nd attack won't knock him out. My concern is powering him up. I though of the Eel, Emboar etc. But after seeing all the MTCs I think Celebi Prime would work, heck you could possible do 80 damage turn 1 if you play your cards right. But you would start with Celebi Prime power up a Regi fast, and start attacking. You have Tornadus for concerns of weakness. Shaymin EX for late game comebacks and Shaymin celebration wind to move energy around if needs be. It is an idea on paper, not tested but I like the idea
Pokemon
4 x Celebi
3 x regigigas EX
2 x Tornadus
1 x shaymin ex
1 x shaymin
Trainer/Supporter/Stadium
4 x Pokemon Collector
4 x Eviolite
3 x Pokemon Catcher
3 x Junk Arm
4 x Professor Juniper
4 x Professor Oak's New Theory
4 x Sage's Training
2 x skyarrow bridge
3 x Switch (not sure if I need this)
2 x Revive
Energy
4 x Double Colorless Energy - Special
10 x Grass Energy - Basic
2 x prizm
Pokemon
4 x Celebi
3 x regigigas EX
2 x Tornadus
1 x shaymin ex
1 x shaymin
Trainer/Supporter/Stadium
4 x Pokemon Collector
4 x Eviolite
3 x Pokemon Catcher
3 x Junk Arm
4 x Professor Juniper
4 x Professor Oak's New Theory
4 x Sage's Training
2 x skyarrow bridge
3 x Switch (not sure if I need this)
2 x Revive
Energy
4 x Double Colorless Energy - Special
10 x Grass Energy - Basic
2 x prizm