The best team is the one that compliments each other's weaknesses but since the game's difficulty is really not that hard, any team is acceptable as long your Pokémon's levels are high enough for the respective battles.
one fire type one water type one grass type and your favorite Pokemon. It would also help to have a Pokemon that knows stun spore, yawn, hypnosis, ect.
In my opinion, there is not a "best team". Take your most powerful Pokemon of major types, and battle with those.
there isn't really a best team i find a team with well balanced types i know the best team to use on the Pokemon league is just a blazeiken and a salamence so that might work on the battle frontier aswel and with that a good water Pokemon and that should work
Team Mystic is the most popular one.
Zapdos, Kyogre, Mewtwo, Articuno, Groudon, Rayquaza.
You can find help for a team for Pokemon Y on the website US Game.
pokemon Y
There is no best team unless you hack it. any pokemon can be good if trained correctly
my team
The best Pokemon team in diamond is piplup, shinx, starly, machop, budew, and cranidos
one fire type one water type one grass type and your favorite Pokemon. It would also help to have a Pokemon that knows stun spore, yawn, hypnosis, ect.
Well my team was Wigglytuff charizard
charmander
By Strategy, if you mean best team of Pokemon, i recommend a solid team with a Dark,Psychic,Dragon,Water,Fire, and a Fighting Pokemon.
My team name is simple "Team Pokemon" because I plan to recruit all the Pokemon I can.
There is no defined "best team" in any Pokemon team. What your idea of a best team, may be different than someone else's idea. Use the Pokemon you like, and train them to high levels. You can use any Pokemon you want, as long as you teach them the right moves, you can't lose.
In my opinion, there is not a "best team". Take your most powerful Pokemon of major types, and battle with those.