Sherman Filterbank hands down! It’s the king of stomp! Pricey but depends on how much you want to go with the tone. The other two would be Bomb Factory’s Sansamp PSA 1 Plug in. It's cheap and warm tone sounding crunch or GRM Tools Plug ins bundle, It's great for sound design.
I own a Filterbank , you wouldn’t be disappointed!
http://www.sherman.be/