Methane in the atmosphere of Saturn's largest moon Titan, and the planet Uranus.
These are spectra of Titan (red line) and one I did earlier of Uranus (blue line). Both are dominated by methane absorption bands - the dips in the smooth shape of the overall curve.

Titan is obviously a much more orange colour than Uranus' blue-green, shown by the larger amount of yellow to red light, compared to the high amount of blue and green colours in the curve for Uranus.