RE: Keldeo EX / Blastoise (With and without Black Kyurem EX)
My first experimental take on the deck in the future would have a Ball Engine including Level Ball, 1-2 Exeggcute, 3 Tropical Beach, 4 Juniper, 3 Colress, and 4 Super Energy Retrieval with a focus on Black Kyurem EX. The plan is the high amount of PokeBall cards allows me to play Colress well earlier in the game (with the higher Tropical Beach count making a smaller Colress plenty safer while having the extra shots at discarding Frozen City). The main reason for Level Ball is for the Exeggcute (and Squirtle, I guess), and dropping them and Energy in the discard pile with Professor Juniper and Ultra Ball turns Super Energy Retreival into a one card combo that pushes Black Kyurem attacking each turn.
Pokemon: 12
3 Blastoise
4 Squirtle
2 Black Kyurem EX
2 Keldeo EX
1 Exeggcute (PS: This card is the most beautiful card; ignoring the fear of donking, I would play 2 with 4 Ultra Ball without a doubt in my mind)
Trainers: 38-40
4 Professor Juniper
4 Skyla
3 Colress
2 Random Receiver
3 Tropical Beach
1 Dowsing Machine (The decent set-up card, turns into important trainers, becomes a supporter when the hand is lacking, lets the hand work well late game, etc.)
4 Super Energy Retrieval
3 Pokemon Catcher
4 Rare Candy
3 Ultra Ball
2-3 Level Ball
3-4 Energy Search (Extremely versatile with the energy types, is searchable, thins the deck, and is safe because of Super Energy Retrieval's turning into sufficient energy. It's also best to have enough outs to energy, and I'd rather not have 4 Cilan running around)
2 Float Stone (Keldeo EX's most lovely combo)
Energy: 9 (Super Energy Retreival is all you need, and might even be safe to have lowered if you can get the energy in your hand/in play/in the discard okay)
2 Lightning Energy
7 Water Energy
I feel the list is a bit cluttered, but I personally love the idea so far. My instinct is that a better list would have 4 Ultra Ball to discard Energy, 4 Energy Search, and less than 9 Energy. However, this is completely untested, but I'd like to see how this works.
That's my idea on a Black Kyurem focused deck.
~L_X_F