Is there an implant to increase the yield of mining drones? I have found a couple that say boost pilot’s skill at mining. (Inherent Implants ‘Highwall’ Mining MX-1001)
No, there’s no such implants.
The first bonus to mining drones yield is role bonuses of Industrial Command Ships: Orca, Rorqual and Porpoise
Skills Mining Drone Operation and Drone Interfacing also improves their mining yield
There’s a rig or two as well, iirc.