Small changes concerning balance, gameplay, or graphics.
Spaghetorio is a Factorio mod that trades efficiency for glorious complexity, introducing new items, fluids, buildings and science packs to create absurdly intricate production chains. Currently in early alpha with players just reaching orbit, the mod is open for feedback to help tune balance.
Large total conversion mods.
Lua libraries for use by other mods and submods that are parts of a larger mod.