PNR stands for Paranormal Romance which is defined as a literary subgenre of the romance novel. A type of speculative fiction, paranormal romance focuses on romance and included elements beyond the range of scientific explanation, blending together themes from the genres of traditional fantasy, science fiction, or horror. Paranormal romance may range from traditional category romances, such as those published by Harlequin Mills & Boon, with a paranormal setting to stories where the main emphasis is on a science fiction or fantasy based plot with a romantic subplot included. Common hallmarks are romantic relationships between humans and vampires, shapeshifters, or fantastical beings (the Fae, Elves, etc.). Novels of the genre include the Dark Guardian series by Rachel Hawthorne, and Paranormalcy by Kiersten White.
Beyond the more prevalent themes involving vampires, shapeshifters, ghosts, or time travel, paranormal romances can also include books featuring characters with psychic abilities, like telekinesis or telepathy.
Paranormal romance has its roots in Gothic fiction. Its most recent revival has been spurred by turn of the century technology, e.g. the internet and electronic publishing. Paranormal romances are one of the fastest growing trends in the romance genre.
UF stands for Urban Fantasy which is defined as a sub-genre of fantasy defined by place; the fantastic narrative has an urban setting. Many urban fantasies are set in contemporary times and contain supernatural elements. However, the stories can take place in historical, modern, or futuristic periods. The prerequisite is that they must be primarily set in a city.
Urban fantasy describes a work that is set primarily in a city and contains aspects of fantasy. These matters may involve the arrivals of alien races, the discovery of earthbound mythological creatures, coexistence between humans and paranormal beings, conflicts between humans and malicious paranormals, and subsequent changes in city management.
Several characters of urban fantasy are shown to have self-esteem issues or tragic pasts. These matters often tie into the larger story or the development of the protagonist. Though stories may be set in contemporary times, this characteristic is not necessary for the fiction to be considered urban fantasy, as works of the genre may also take place in futuristic and historical settings, real or imagined
(Information obtained here is from Wikipedia.org)