I highly doubt that any two pokemon of the gang will have same attacks. I mean tackle/quick attack are alright. Those are the commonest there are, but a move like Brick Break can not work for two pokemon of the gang. Did any two from Ash and May had a common attack?
Bulbasaur/Bulbasaur: Vine Whip (I think)
Combusken/Torkoal: Overheat
More recently...
Glaceon/Pikachu: Iron Tail
MY next attack for main guys pokemon
Ash:
Pikachu - A 5th gen move not to be seen for awhile
Gliscor - Needs ground move so earth power would be great
Buizel - Ice Punch(i'm almost certain on this)
Monferno/Infernape - Flare Blitz upon evolution........or Close Combat(kinda unlikely)
Grotle - I can kinda see it being Cunch.........or leaf storm( unlikely due to razor leaf)....just another grass den
Staraptor - It's done i'd say but Swift if it needs a new one
Brock:
Happiny/Chansey - Egg Bomb
Croagunk - Sludge Bomb
Sudowoodo - Think it's done but Rock Tomb would be it's next one
Dawn:
Mamoswine - Blizzard
Pachirisu - It's done......unless they give it a move it can't use......Thunderfang
Buneary/Lopunny - Dis is tricky...it has to learn a new move but i'd say either Jump Kick or Endeavor
Piplup - Drill Peck and Hydro pump in either order