Providing the player with new tools or adjusting the game interface, without fundamentally changing gameplay.
Collections of mods with tweaks to make them work together.
Prevents death by [jerk] trains. Credits to cdaringe for the original, all I did was update factorio version. See the original mods.factorio.com/mod/nice-try-train for a working version (0.18 support has been added)
Mods introducing new content into the game.