Well potassium nitrate is a pretty strong oxidiser. Mill it with a pestle+mortar and mix it with icing sugar 1:1 by mass. Put 30-40g on some alu foil. Setting

Well potassium nitrate is a pretty strong oxidiser. Mill it with a pestle+mortar and mix it with icing sugar 1:1 by mass. Put 30-40g on some alu foil. Setting fire to that will produce crap loads of smoke very quickly. I filled my entire garden up with smoke with one of them a couple of years ago. Sure there are more in that list but that strikes me as the most obvious.