So as I feared and suspected, there isn’t an easy answer. Below is a list of powders I think I should keep an eye out for:
IMR 3031
IMR 4064
H335
CFE 223
AA 2230
AA 2520
BL(C) 2
Varget (though I’ve never seen it in stores even in late 2019)
Edited to add:
TAC
8208 XBR
Any of these seem like they would work well in 223 and 308 and might work in 30-30, though I’m sort of looking for Unique or similar for that one to use with my upcoming casting endeavors.