I stumbled into the synthetic tag, currently featuring:
Redundant taggings on android/robot/cyborg characters
synth_(vader-san)
post #2604950
protogen
post #2533763
An android cat
post #2239017
Furrified Warhammer 40k necron
post #2715843
Furrified D&D warforged
post #2701432
A taur with cybernetics
post #2765945
bionicle toa
post #2415545
Et cetera.
Rubber and latex creatures
Bioengineered fully-organic character
A character whose owner holds the FA username 'synthetic'
Should this be sent to a disambiguation, or invalidated?
There are existing tags for almost every use-case, synthetic itself has no wiki, and its tagging has been mixed as far back as September 2015. I probably should have caught this back when I made the cybernetics BUR
Updated