Great one but just one move that can be strong when pokemon with items will be allowed to trade from black to older versions .
Move explosion .
Item Normal Gem .
Power 250+ 30%(Gem) +Stab
= 250 + 30/100 X 250 + 50/100 X 250
=250 + 200
= 450 .
Now remember , prior to black and white , the move explosion temporarily halved the defence stat of the opponent , i.e. doubling its power with takes it to a staggering 900 POWER .
But , as i said this would work ONLY after trading from black/white to previous versions will be enabled .
So , just a teaser yet . :)