If I had to pick one Warhammer book to translate into a movie it would be Gloomspite. It has everything
>Thing like Body Horror
>28 Days later style Zombies
>Mass scale epic carnage
>Tonnes of extremely brutal comedy horror
>Cosmic Horror
>Night Goblins are basically methed out psycho murder children with knives, which makes them very funny while terrifying.
Book also has a phenomenal murder mystery/political thriller lead up to the point where shit just goes completely fucking batshit. Another point that is phenomenal about the book is how well it describes and visualizes all the horror and feeling of the moment, you can feel the mushrooms ripping out of peoples eyes and skin and mouths, you can visualize the Bad Moon rising over the city, the amazingly written violence.
Honestly, for me, best BL book out there, at least in terms of Horror, and it's the one that absolutely should get a film adaption. Only negative downside is that it's fucking Age of Sigmar, but that really doesn't have any bearing on anything I guess, it's city guard/mercs vs Night Goblins.

Would kill for this to get adapted into a film. Probably one of the best horror books in actually visualizing a totally fucking batshit Cosmic horror situation that feels like it would translate to screen amazingly. Especially when you realize Goblins are essentially children, hopped up on psychedelics and meth and running around with knives murdering people.
Great body horror in it as well.
Sadly we will only get 40k slop on screen, but if I was heading GW, this is the one I would want to get put out there and made into a horror movie with a director that has a great eye.