If i understood what you're looking for, there are 3 doodads that have a light attached i can think of: torch, blue mushroom, and streetlamps
to make lights in a map i usually take one of these and scale it down to 0.01 (almost invisible ingame, especially if you hide it inside or very close to other doodads).
The torch has a small fire particle attached to it, not really noticeable ingame,
the blue mushroom has a very evident effect (blue pulse) easily visible ingame
while the lamp has no attached effects, so i usually prefer this one