New things that follow idea of vanilla game
Mods introducing new content into the game.
Augmented or new ways of transporting materials - belts, inserters, pipes!
Furnaces, assembling machines, production chains.
When creating large builds with the mods assembler, the limiting factor is the low vanilla pipe throughput. I suggest adding new pipes that allow the fluid to move faster (something similiar to https://mods.factorio.com/mod/high-pressure-pipes)