He's my favourite disney villain only from Jake and the Neverland Pirates and Peter Pan Returns.

Oh there's no doubt here, Hades of course. They made a good team in Hercules the Arabian nights crossover and even if this crossover wouldn't appear, they are such a funny duet:) Both hot-tempered both crave for the power
Jafar doesn't get impressed by the idea that Hades is a god (and stays same all along) while Hades first dislikes him but then somehow they find common language and this is wonderful

I think Hades from Hercules and Captain James Hook from Peter Pan will be Jafar's Best Friends.