Ummm. You forgot Dratini.
I choose the Dragon Pair, The Ball Pair are Modern Pokemon, While Dragonite, Dragonair, Dratini may came from the Ancient Times. But it's just me.
If you let me review those cards, the effect of Dragonite's Second attack's damage is very much underpowered if it has an effect like that. I suggest you to change it to 2 instead of 6. Then about Dragonair: Its first attack is overpowered.
Electrode is okay, same as Voltorb, but Electrode's Body should be a Power.
9/10 for Ball Group
7.5/10 for Dragon Group.
I have chosen the Dragon Group if you ask me.