#20: Sabrina
because she does a lot for her own Pokemon.
 
#19: Brock's Diglett
because it can kill Jigglypuff in a couple moves
 
#18: Koga's Pidgey   
because it is Pokemon searcher with wings
 
#17: Erika's Ivysaur
because of the double razor leaf can do 80 in two flips
 
#16: Blaine's Dodrio
because it can deliver 50 in a one hits   
 
#15: Promo Dragonite
because in one flip it can kill low level pokemon
 
#14:Brock's Dugtrio
because on it Earthquake attack
 
#13: Sabrina's Jynx
because of it's Helping Hand  can draw you a lot of cards in only one energy
 
#12: Sabrina's Haunter
because of Night Spirits it can do a total of 150 (if lucky and have a full bench of Gastlys and the rest).
 
#11:Sabrina's Golduck
because of the damage shift because it acts like a Alakazam.
 
#10: Rocket's Mewtwo
because it has three attacks and of Psyburn.
 
#9: Rocket's Zapdos
because of the high hit points and damage
 
#8: Koga's Beedrill
if you are lucky it is a good card and it deal out  a cool 70 damage
 
#7: Giovanni's Machamp
because it can deal out a big 120 damage if coin flip is good.
 
#6: Sabrina's Alakazam
because it can do 60 and if you have two alakazam it can swap damage.
 
#5: Sabrina's Gengar
Shadow Bind makes you not retreat next turn.
 
#4:Erika's Venasaur
because it does 20 direct and does 20 to two benched pokemon
 
#3: Giovanni's Nidoqueen
Because of the Love Lariat it can do 0 or 100 if you have a Giovanni's Nidoking on bench
 
#2: Giovanni's Nidoking
because of Rolling Attack can do 40 or 70
 
*****#1********
Blaine's Arcanine
because it can 40 or 120 it can kill a Charizard in one move.
 
Email me at raging_flames2005@hotmail.com if you have any other suggestions.