Quake 1 torches/flames:

At the request of many people on the RUST discussion board and others, I have added the torches and the flames from the original Quake.

This is probably one of the simplest things to do, just add a light_torch entity or a light_bigflame or a light_smallflame entity. If you use Qoole or Worldcraft and you have installed the entity definition files, you should have these entity defined for you already. All of these are standard light entities so you can add fields like light (amount of light) style, colour etc.