No, this isn’t a cast iron thing. Using stainless pans, you can get nonstick effects that, in my experience, far outperform Teflon anyway. The process is called “spot seasoning.” I have cooked crispy, cheesy rice noodles with eggs with zero sticking.
I love my cast iron pans, but stainless is my daily go-to. Added bonus: use 100% copper wool to clean your stainless pan. The copper-coated wool at most grocery stores is problematic; you might get a few uses out of the coated garbage and then it starts shedding metal bits.
Oh yes, I didn’t say it but I agree with your idea of slate, I personally would love to try it even though I know that will never happen!
I suppose what I meant is, in my experience, there are so many different materials made for so many different industries… a lot of times one exists already for extremely cheap in a place you just wouldn’t think to look.
Not being very experienced with slate myself, I’m not sure if it’s uniform on the surface or how much prep it would take? I know from grinding lenses that as much as we think you can just press two surfaces together and they’ll become flat, the opposite happens. So I’m thinking of slate and thinking how neat it would be if you could plane it down, but I’m also thinking of what else!