Blue/Green/Gary-A complete and total evil...well, I won't say what I think he is, but he's just...THERE
Silver-He's basically your average power-hungry angsty teenager
Brendan/May-GAHAHAHAHAHAHAHAHAHAH-oh my aching ribs-GAHAHAHAHAHAHAHA
Wally-Wait, he's a rival? *sweeps him away*
Barry-Never...EVER give him a car, Palmer, I beg you-weak weak weak
Cheren-Like Silver, but more of an idiot
Bianca-Barry the crossdresser! A complete and total ditz, filling the dumb blonde stereotype perfectly (sorry to any blondes)
N-a young man driven by ideals and seeking the truth behind what makes pokemon so powerful, despite us apparently weakening them by interacting with them
So, Green, Silver and N are the only REAL Rivals
everyone else...no
(yes, I'm biased for N, what of it?)