K: Unlocked – Overclockable, usually higher binned CPUs.
F: Disctrete GPU Recruired – The iGPU is disabled in this chip, prolly due to defects.
S: Special edition – The Creme-de-la-Creme of a lineup, basically the highest binned chips. (Fun fact: In the earlier days ‘S’ used to mean Low Power)
T: Low Power – A “35w” chip used in smaller form factor OEM pre-builts.
G: High Performance iGPU – An APU with an iGPU that doesn’t suck arse, they don’t make these on desktop anymore though.
X/XE: Extreme Edition – High end, unlocked CPUs with a PPG equivalent to diamonds, they lack an iGPU, though include some more niche features.