Will Cogley has some extremely useful well done youtube videos and information on things like building 3d mechanical eyeball movements and the actual realistic eyeballs as well as robotic hands including very detailed discussions of human hand anatomy!
Check Will Cogley’s videos out on YouTube and be very impressed! Yes he does admit that he has learned from the skills of the many robot and animatronics experts who have come before him. https://www.youtube.com/c/WillCogley/videos