Well you already know that each pokemon has a weakness well this is a list of types and recomended pokemon for each gym battle

brock=water or grass, squirtle or bulbasaur
misty=electric or grass, picachu or bulbasaur\ivysaur
LT.surge=rock or ground, geodude or onix
erika=firetype or flying,charmander\charmeleon\charizard or pigetto\pigeot
koga=fire type or water type, charizard or blatoise
sabrina=fire type water type or grasstype, venusaur blastoise or charizard
blaine=water types only, blastoise polywhirl or gyarados
giovanni=kind of like brock so use the same type nextthe elite four
lorelie=water type fire type or psyhic,blastoise charizard or alakazam
bruno=grass type or water type, venusaur or blastoise
agatha=fire type or ice type= articuno seel or blastoise
lance=first pokemon electric type then ice type for the rest,artico or zapdos

champion gary in one of my other cheats

If you want more detail e-mail me.