Ill break down all the abbreviations I see here
These three are the most popular books used for studying the MCAT
EK1001 - talking about the examkracker series used for MCAT biology, physics, chemistry, organic chemistry (OCHEM), verbal reasoning (i.e. really long paragraphs)
TPRH- the Princeton review hyperlearning series, another series used for MCAT, also covering bio, physics, chem, verbal and ochem
TBR- the Berkrley review series, the third series used for MCAT, also covering bio,physics, chem, verbal and ochem
Other abbreviations seen:
SN2-the definition was covered by medic86 above me
FL- a practice MCAT test that can be bought by the AAMC
VR- verbal reasoning
Those are the only abbreviations I can think of that I seen a lot here on MCAT discussion