That depends on which Pokemon you think are good ones. Here are some that I think are good:
Search for them or trade
You can find help for a team for Pokemon Y on the website US Game.
Parfum Palace. Find the owner's Furfrou and he will give you it.
*Mew is not catchable in Pokemon x and y, but you can get him online from wondertrades and such. Mewtwo however, is catchable and you can find him in the cave in pokemon village.
A, B, Y, A, A, Y, A, Before the ball turns yellow
Good physical sweepers in Pokemon X and Y are Mega Lucario, Mega Mawile, and Heracross. Other good special sweepers in Pokemon X and Y are Manectric, Alakazam, and Mega Gengar.
You can find a good selection of pokemon party supplies on Amazon.com. You can check out what they have to offer here: http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=pokemon+party+supplies&x=0&y=0
You may be able to find someone to trade a Special Torch for Pokemon C or Y in a Pokemon Facebook group.
You will have to transfer it from a different Pokemon game
You can find a Rhyhorn at the 3D area of the Glittering Cave.
gamestop Pokemon platnums good.
Laverre City and the Route under it.