New places to build more factories.

Transportation of the player, be it vehicles or teleporters.

Augmented or new ways of transporting materials - belts, inserters, pipes!

Trains are great, but what if they could do even more?

New ways to deal with enemies, be it attack or defense.

Map generation and terrain modification.

Things related to oil and other fluids.

Furnaces, assembling machines, production chains.

Changes to power production and distribution.