For explosion and fire effects check
this link (It's youtube link, I belive it is safe to link it).
Simple command "fire" will give you high flame that is not effecting Sims. Gobias Cofi not only didn't react to fire, but he walk trough it without second thought, so I believe it is just a visual effect.
As for other effects, there are rats and many other, from train in France to water jets in science facility fountain. I mostly use water effects, and am not familiar with fire that much, but in combination with gas effects you can make what every you can think of in that dungeon.