(oh man, MineChem was
brilliant. Loved that mod.)
Metallurgy.
@Tyler_BMN Atomic Science was one of the staples of the old Voltz modpack. Voltz hinged around the Universal Electricity mod, which made it quite nice to use as pretty much all the mods tied into UE. Atomic Science had multiblock fission and fusion reactors, as well as particle accelerators/colliders. It has some nice models, nice complexity, and was pretty good fun!