Gothic Grain is a LoRA that creates a grainy or grunge style. It mostly does drawings in monochromatic, but it can also be used for real images, if explicitly specified.
Structure your prompt like this:
Flux
A damaged monochromatic drawing with rough line art and flat colors and strong grain about {your tags}. The image is covered in heavy grain and vintage dirt and artifacts.
Illustrious
gothic, monochromatic, digital illustration, flat colors, line art, vintage dirt, artifacts, heavy film grain, {tour tags}, dark atmosphere, eerie