Fair input, useful output: mall, factory, logistics, and mod-content package recipes for players who still build the belts themselves.
Mods introducing new content into the game.
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.
More than just chests.