The genres most in demand, accord to literary agents' announcements of what they are seeking in 2023 are:
1. Young Adult (YA), YA magical, YA science fiction/fantasy, YA LGBTQ & POC (people of color), YA classics retold
2. Romance, sweet/swoon-worthy romance, LGBTQ romance
3. Fantasy, fantasy romance, fantasy with magic & witches, fantasy set in a non-western country
4. Horror, ghost stories, supernatural horror, lite horror, survivalist/isolationist horror
5. Middle grades, middle grades with POC, middle grades with fantasy, middle grades with a strong message
There are 4 genres traditional publishers don't want. For a book to be accepted by a publisher, it must fit into their format/sales structure, etc. Here's what big publishers don't want:
1. novellas (20,000-50,000 words; usually they want 60,000-90,000
words)
2. poetry (too small a readership)
3. short story collections (too small a readership, although anthologies with well-known authors can work)
4. faith-based books (the popular Christian publishing space is separate)
New & fairly new genres/sub-genres:
techno-horror
dystopian literature
refugee literature
self-help literature
the weblog
hyper-poetry (with links and hypertext)
the graphic novel (comic book)
doodle fiction - combination
flash fiction - usually short
creative non-fiction
Keep in mind that a book can fit into more than 1 genre at once. For example, historical fiction that is also a romance is pretty common.
Post Scripts from the Attic
This is the amazing library (15 years old) at Alexandria (Egypt), a resurrection of the Ancient Library of Alexandria. I'm told it's massive and extremely impressive, so I'm not sure why we never hear about it:
Very helpful information, thanks.