Flexion:
https://flexionextruder.com/

or

Titan:
http://e3d-online.com/Titan-Extruder...FSsW0wod10wE4Q

These are the top end solutions on the market right now. Flexion is a direct drive in the sense that the hobbed gear sits right on the stepper motor shaft 1:1 but it has a brushed wheel that keeps the hobbed gear clean.
The titan has 3:1 gear reduction for finer precision or more steps/mm of filament travel 3x more and also all the extra torque that comes with 3:1 gear reduction.