If there is anything not here have a look at the Urban Dictionary. And maybe let us know so we can add it.

Item Definition
AlphaAlphas are dominant, sexually aggressive, and able to breed
ARCAdvance Reader Copy
BABad Ass
BBFBook Boyfriend
BBWBig, Beautiful Woman
BDSMBondage, Disipline/Dominance, Sadism, Masochism
BetaBetas are submissive but may possibly breed omegas
BLBoy Love
BWWMBlack Woman, White Man
DAPDouble Anal Penetration
DDLGDaddy-Dom, Little Girl
DNFDid Not Finish
DPDouble Penatration
DubconAn abbreviation of "dubious consent." While both parties might be willing, but they might also not be. Caught up in the moment, neither can stop the sex, but often they don't know if they want to.
DVPDouble Vaginal Penetration
Fast BurnThis book has guaranteed sex scenes
FFFan Fiction
FFFemale/Female pairing
FMCFemale Main Character
FWBFriends With Benefits
GNOGirls Night Out
H (Captialized)Hero
h (lower case)Heroine
HEAHappily Ever After
HFNHappy For Now
IRInterracial Romance
J/PJealous / Possessive
KAKick Ass
Knife PlayUse of a knife to enhance a sexual experience
KnottingA male and his mate have a sexual experience like canids. Canines have a gland (the Bulbus Glandis) in their penis, often called a knot, which swells during intercourse. It allows for the penis to be locked inside during penetration. Partners can often struggle to take this, but experience extreme sexual pleasure when they do. Taking a knot often has emotional significance as well. Sexual partners often are locked together for extended periods after sex until the knot subsides.
KUKindle Unlimited
Large Harem7 or more members
LGBTQIA+LGBT(QT+) Lesbian, Gay, Bisexual, Trans, Queer, Inter, Ace, Others
LitRPG Literary Role Playing Game
May-DecemberAge-gap relationship
MCMotorcycle Club
Medium BurnSexual interactions and there might be sex
Medium Harem5 or 6 members
MFMMale, Female, Male (Males do not interact with each other)
MM or M/MMale, Male
MMCMale Main Character
MMFMale, Male, Female (Males do interact)
MPregMale Pregnancy
NANew Adult
NSFWNot Safe For Work
OMOther Man
OmegaOmegas are the lowest-ranking members in the group. Often, their primary function is breeding. They may be rare and prized.
OmegaverseA society where humans follow the hierarchical structure of wolf packs. This is most common with shifter stories, but is also seen in realities with no supernatural element. The hierarchical structure includes Alphas, Betas and Omegas. In MF books, there are usually only one Alpha and multiple Betas, but this dynamic can change within RH stories. Omegas are often rare in packs/groups.
OWOther Woman
PeggingWhen a woman penatrates a male with a strap on
PNRParanormal Romance
POCPerson Of Color
POVPoint Of View
PWFParanormal Womans Fiction
RHReverse Harem
Slow BurnNo sex in the first book, sexual interactions may be limited
Small Harem3 or 4 members
TBRTo Be Read
UFUrban Fantasy
YAYoung Adult