Battle Pyramid
Team used for Silver Symbol: Regirock, Regice, Registeel
Team used for Gold Symbol: Articuno, Zapdos, Moltres
At the end of your 21st Floor you get challenged by the Pyramid Leader. Beat him and you shall get the Silver Battle Pyramid Badge
At the end of your 70th Floor (Through it 10 times) you get challenged by the Pyramid Leader. Beat him and you shall get the Gold Battle Pyramid Badge
I tend to use Pokémon with high defense for this tournament.
Metagross is alright, but Earthquake really gives it a hard time. A fast Fighting Pokémon can be useful for the first time around, and a Rock type attack really takes out the Gold Symbol.
Battle Palace
Team used for Silver Symbol: Crobat, Slaking, Lapras
Team used for Gold Symbol: Arcanine, Slaking, Suicune
After 21 Consecutive Wins (1 on 1 Only) you get challenged by the Palace Leader. Beat him and you shall get the Silver Battle Palace Badge
After 42 Consecutive Wins (1 on 1 Only) you get challenged by the Palace Leader. Beat him and you shall get the Gold Battle Palace Badge
The best plan for this contest is to have a team made specifically for it. You need natures that work with the attacks. That may mean that all you E.V. trainers will have some bad stats, but it will be tons eaiser to win. You have to let your pokémon work. It can't sit there because 'Metagross wasn't able to use it's attacks'. It doesn't work, trust me.
Battle Arena
Team used for Silver Symbol: Heracross, Umbreon, Shedinja
Team used for Gold Symbol: Umbreon, Gengar, Breloom
After 27 Straight Battles & Wins (1 on 1 Only) , the Arena Captain appears and challenges you. Beat her and you get the Silver Battle Arena Badge
After 56 Straight Battles & Wins (1 on 1 Only) , the Arena Captain appears and challenges you. Beat her and you get the Gold Battle Arena Badge
A Pokémon that has plenty if attack and a fair amount of speed fares well here. I used Salamence, Metagross and Tyranitar here, in that order. They were very useful, and I quickly gained the Silver Symbol.
Battle Factory
Team used for Silver Symbol: Randomly Generated
Team used for Gold Symbol: Randomly Generated
The only good idea here is to pick Pokémon who's types counter-act each other.
Battle Tower
Team used for Silver Symbol: Alakazam, Entei, Snorlax
Team used for Gold Symbol: Raikou, Snorlax, Latios
After 35 Consecutive Wins (1 on 1 Only) you get challenged by the Tower Leader. Beat him and you shall get the Silver Battle Tower Badge
After 70 Consecutive Wins (1 on 1 Only) you get challenged by the Tower Leader. Beat him and you shall get the Gold Battle Tower Badge
Battle Dome
Team used for Silver Symbol: Swampert, Salamence, Charizard
Team used for Gold Symbol: Swampert, Latias, Metagross
At the end of your 5 Consecutive Wins in Tournements (A Total of 19 Battles) (1 on 1 Only) you get challenged by the Dome Leader. Beat her and you shall get the Silver Battle Dome Badge
At the end of your 10 Consecutive Wins in Tournements (A Total of 39 Battles) (1 on 1 Only) you get challenged by the Dome Leader. Beat her and you shall get the Gold Battle Dome Badge
Battle Pike
Team used for Silver Symbol: Seviper, Milotic, Shuckle
Team used for Gold Symbol: Seviper, Gyrados, Steelix
At the end of your 28 Consecutive Wins or Room Completions, you got notified by the owner about the trainer, go to the far right room and you'll be challenged by the Pike Champ. Beat her for the Silver Battle Pike Badge
At the end of your 140 Room Completions, you got notified by the owner about the trainer, go to the far right room and you'll be challenged by the Pike Champ. Beat her for the Gold Battle Pike Badge
All I can say is that Metagross is the one Pokémon that is ideal here. It takes the Silver Symbol out in a flash. It's only problem with the Metagross and it's Earthquake TM, so just counter-act that with a Water type Pokémon