Arman Madani on statecraft.beehiiv.com provided a simple statistical analysis of over 1,000 banned books along with the raw data.
About half of the books are about Activism and Social Justice.
A quarter are LGBTQ+ specific, many deal with mental health issues.
About a fifth are related to race.
A fair number (7%) were about women that did important things. I was surprised by this. I hadn't realized that the idea that some great leaders and scientists are women was such a dangerous idea.
My suburban children's library in the 1960s would have had reservations on about 0.1% of the books.
Less than (2%) were rated at 17+. I went through the entire list, and there were precisely two books that I think the children's section of my New Jersey small town library in the 1960s would have had reservations about. They are books that would have been useful and, I think, appropriate, but I don't think our librarian would have agreed. So two books out of 1600, about 0.1%.
Only one of the 17+ books is listed as having an illustrator. Y: The Last Man is a science fiction graphic novel. I couldn't find a single non-G-rated image in the collection. None of the others are listed as having illustrators, though I presume some other pictures. From the titles, they seem unlikely to me to be erotica.
Madani's article has further damning commentary on the book banning; the closer you look, or more indefensible the practices seem.