What do you mean when you ask for something to "up" your sound?
There are other options out there, but do you want something that sounds smoother and bassier, or do you want something with more high end to it? (etc etc)
Nordstrands are a favourite for the vibe of the original MM pups.
Seymor Duncans do a few aswell, Quarter Pounders being a staple choice.
Bartolini do a few aswell, mainly more subdued sounding.
Delano do a few which are quite interesting, such as one which gives you a J-style option at the bridge.
(the options go on!)
Going to have to be more specific, and tell us what you are looking for, for us to be able to try and help
