>>20119517Generally Fighting is your best option for a disguise, since it baits out things that are immune to it like Gengar, or things that can destroy it like Lati@s. Then you can pull out a surprise dark pulse and KO it.
Ghost is another decent choice if the opponent falls for the illusion, but since most ghost-types are special people tend to counter with special walls. Zoroark really has a hard time punching through them if it's not running choice specs.
Like someone else said, Aegislash is a pretty useful disguise since Zoroark can wipe out its common checks like Scizor and Ferrothorn.
>>20119482I'd really prefer it gets a bit of a speed buff to go with that so it doesn't lose out to anything with a scarf, as speed and power are the only things Zoroark has going for it.