In many fantasy books and movies, like Harry Potter for example, there are wizards or priest who perform "fire magic" by throwing various powders into a fire cauldron. The effect is a poof of smoke or a flash. I guess the intent is to evoke some spirit or something. My question is what agents were known or could have been known back in the age of alchemy that could produce any interesting effects. I just need some descriptions or leads for historical research and am not intending to experiment. I am not seeking anything dangerous or explosive, just some cheap effects that could have been known to magicians of maybe a 1000 years ago. My inquiry is therefore possibly historical as well as pertinent to chemistry.