Which abbreviations are unclear? Here are a few defined start out with, based on recent stories:
AP = age progression
AR = age regression
BBW = big beautiful woman
DG = downgrade (generally applied to a downgrade in the character's life status)
IQ = intelligence quotient (in other words, loss of intelligence)
MC = mind control
SSBBW = super-sized big beautiful woman
TF = transformation
TG = transgender
TR = transracial
WG = weight gain
Good sites to check out acronyms are
AcronymFinder and
Urban Dictionary.