they have unnecessary EVs. and as far as i know, you can ev raise them even after level 100 (for black white)! :D anyway, heres the list:
iv - iv check; ev - ev check; reduce - reduce all evs back to 0 (if ever they have evs); clone - clone (clone after doing the iv, ev checks and AFTER reducing the evs) :)
breloom - iv ev
whimsicott - iv ev clone
thundurus - iv reduce clone
emolga - iv reduce clone
dragonite - iv ev
blaziken - iv ev clone
lucario - iv ev clone
togekiss - iv evclone
dusknoir - iv ev clone
you can keep a clone or two as payment! :D