I've stumbled upon this Lora while browsing Pixiv for guro loras
https://civitai.com/models/519359/coffinponyv3

It's a PonyXL Lora for making girls in coffins. Looks very neat. Covers a very niche fetish. It has a wide variety of types in this one lora. Lots of trigger words if you want certain features.

Details on how to use is in the civit link

Author is 希曼 (https://www.pixiv.net/en/users/87100563).
You should check them out. Hope they make more and better loras like this!