Expanding Atmosphere Types

[Caduceus]

Of course, dolphins would argue that Earth is a water planet, not an oxygen planet...

So would Magellan.

Other atmospheres - Nitrous, Argon, Fluorine, Bromine

Add sodium as well.

From Google:
Three satellites of the outer planets possess atmospheres. Titan, a moon of Saturn, and Triton, a moon of Neptune, have nitrogen atmospheres. Another moon of Saturn, Enceladus, has an atmosphere composed primarily of water. Other bodies within the Solar System with extremely thin atmospheres are the Moon (sodium gas), Mercury (sodium gas), Europa (oxygen) and Io (sulfur). The dwarf planet Pluto also has an envelope of nitrogen and methane as it approaches close to the Sun, but these gases are frozen for most of its orbit.
Google Atmosphere