In the Battle Frontier, special pokemon are needed to be very successful. Of course any pokemon can fight, but it really does take good training and care to win. I assembled a team that can mostly take out multiple trainers, weaken many pokemon, and defeat the frontier brains. It is true that the frontier brains are hard to beat, especially since they have strong, rare pokemon, but if you can develop a good, well-balanced team, it would be good for the Battle Frontier.

The team I assembled for Battle Frontier:
Ampharos-Thunder,Thunderpunch,Iron Tail,Mega Punch
Octillery-Fire Blast,Ice Beam,Surf,Psybeam
Miltank-Solarbeam,Milk Drink,Focus Punch,Thunder
Houndoom-Flamethrower,Crunch,Hyper Beam,Return
Shuckle-Earthquake,Sludge Bomb,Dig,Toxic
Noctowl-Hypnosis,Dream Eater,Psychic,Aerial Ace

These pokemon have helped me throughout the Battle Frontier. As you can see, they are not Hoenn pokemon, they are Johto pokemon. These rare pokemon can be easily captured in the upgraded Safari Zone after the Pokemon League. After I defeated the Pokemon League, I decided to start on a new team of pokemon, and store up my old Hoenn Pokemon. So, I went to the Safari Zone to capture new pokemon. And I got lucky! I found rare pokemon that helped me out a lot. So, be sure to have a chance to catch some pokemon in the Safari Zone, cuz it can help you out a lot. Make sure your new pokemon team is well-balanced, strong, sturdy, and durable. This new team will bring you success in the Battle Frontier.