Currently, when I walk through clouds of 'stuff' I have no idea what kind of damage it is dealing. I have to wiki it. It doesn't show up in the combat log. In the case where I would want to maybe stack resistances to deal with it when it becomes common enough problem, I have no idea what to get. Do the pumpkins you regularly encounter on 3rd floor use clouds that do, Necromantic, toxic, acid, or putrefying damage. I have no idea.
Well it should be rather obviously toxic damage. The color for one thing but toxic is generally on all poison clouds. Brimstone has asphyxiative, acidic and conflagratory but that'd be hard to find out if you're not looking at the numbers pop up. So yes these should be put into the combat log somehow. Not sure exactly what they'd be called though, maybe the spell names would work but it'd be somewhat odd for some triggered mines.
I have a hard time determining what color those numbers are, they appear far to briefly for me to tell.
Well they mostly have different saturations and luminances as well but yes I thought of that. And even if some are close there's a good chance that you figure out that fire is conflagratory and not toxic.
Most of the fleshsmithing clouds deal some form of asphyxiative and putrefying. Besides the damage type it would be nice to see the exact amount of damage received.