A Factory is optimized. Factorio evolves. Efficiency drives the former; reality shapes the latter
Large total conversion mods.
Augmented or new ways of transporting materials - belts, inserters, pipes!
New ways to deal with enemies, be it attack or defense.
Armors or armor equipment.
New Ores and resources as well as machines.
Things related to oil and other fluids.
Furnaces, assembling machines, production chains.
Changes to power production and distribution.