I know their are many vowel filters that filter your sound to an A E I O U. And they may be a reason for this I guess but I’ve never heard of a consonant filter? I mean wouldn’t that be cool if you could get a P or a Z or something? I may sound stupid But I think that would be a really cool plugin if possible.
Actually that is quite a good idea 
What sound are you making when you hold a peeeeeee or a zeeeeeee or a kaaaaaaaa.
There could never be a consanant filter because its just the definition of the attack of the sound.
Well why can’t attack shape a vowel? I feel stupid haha.