Most of the more capable hands out there rely on expensive, closed, patented systems. While really impressive, few people are going to be able to afford the tens of thousands of dollars a Barrett WAM arm or a Robotiq gripper will set you back.
I stumbled across a whole library of hands put out by the Yale OpenHand project, which has not just one, but a whole library of hands, with the complete files to replicate them:
They even make it easier to attach and swap out hands by providing a common dovetail wrist connection:
University of Athens also has a similar project, inspired by OpenHands, called OpenBionics: