Books that conform to a particular type. The primary school's cataloguing reference Te Patakataka identifies the following fiction genre:

Adventure stories	Alphabet books
Animal stories	Australian fiction. (fiction works about Australia or by Australian authors)
Big books. (Oversize books)	Chapter books (Beginning). Easy chapter fiction written for newly independent readers.
Christmas stories	Counting books
Crime stories	Detective and mystery stories
Easter stories	Fairy tale adaptations. (Modern versions and spoofs of stories based on traditional fairy tales.)
Family stories	Fantasy
Farm stories	Ghost stories
Graphic novels	High interest low vocabulary books.
Historical stories	Horror stories
Humorous stories	Love stories
New Zealand fiction. (Fiction works about New Zealand or by New Zealand authors.)	Pacific Island stories. (Stories with Pacific Island cultural content or themes written in either English or Pacific Island languages.)
Pioneer stories	Plot your own stories
School stories	Science fiction
Short stories	Sophisticated picture books
Sports stories	Stories in rhyme
Supernatural stories	Thrillers
Time travel stories	Toy books. (Pop-up books and movable books.)
War stories	Western stories
Wordless books	Young adult stories

Here is a website which might help you locate books of similar genre, but there are many others.

In some school libraries books of various genre are marked with stickers or labels to indicate genre such as fantasy, science fiction, historical fiction etc.