An absolute majority of the patches had been dialled up from scratch in FM-synths before sampling. I use just a handful of third party presets, and modified them outta their misery
Demo of the sounds:
1.
(the second video showcases a latter addition of electric piano timbres, some are edited 3rd party presets adapted for wavestate).
Link: https://blacksidedsun.gumroad.com/l/phi-mu-labs-1
2.
Phi Mu Labs, vol. II also contains Yamaha DX7-compatible SYSEX files with custom-made patches.
Link: https://blacksidedsun.gumroad.com/l/phi-mu-labs-2