I personally like the long, drawn out suffering. Sure, you can get a boot a foal and be done and dusted. But seeing them suffer, knowing more will come as the mare have more foals like Soylent Brown, Pwease Nu Huwt Babbehs or even “The Fluffy Factory” & “Sunny Gardens” where you can see more stuff being work through then some of the other tropes.
I personally like when misbehaving, at least subborn, mares and foals, starts something like Soylent Brown with Rarity. Put something in a large scale, having it make money, is something I enjoy as you can see something like this happening irl, to a degree.
But for more clean cut gore for gore sake, Subject B07-C comes to mind. I’ve enjoyed it a lot.