so no reactive gasses, what gasses could exist, and how many would be toxic?
so anything that can be oxidized with oxygen in the atmosphere pretty much has been
TL;DR Summary: what kinds of gasses can be in the atmosphere of a planet without killing them or not being naturally possible
I have been creating a fictional star system and ran into an issue, most of the planets atmospheres are not all the interesting, feels wrong to have most be oxygen...