Blaziken Lv.87 or more- Blaze Kick, Double Kick, Sky Uppercut, any of your choice
Crobat Lv.85 or more- Bite, any other Dark moves
Kyrogre Lv.70 or more- Sheer Cold, Ice Beam, Surf, Hydro Pump
3 more of your choosing

These three are the only pokemon that I use to defeat the Elite 4 and Champion.

Blaziken's double kick(or sky uppercut) and blaze kick are enough to take out Sidney's Pokemon. Crobat's dark attacks will take out Phoebe's Pokeemon in a snap. Again you will use Blaziken against Glacia, his/her double kick or sky uppercut will knock each on of them out with one hit. You will use Kyrogre and it's ice beam to take out everyone one of his Dragon Pokemon. Then for the Champion (Steve), I use Blaziken's Blaze Kick on everyone of his pokemon except for Armaldo and Cradily I used Sky Uppercut.

This team has never let me down. I have beat the Elite 4 and Champion 12 times and still going.