Indeed, it's commonly called 'sewer gas' or 'swamp gas' and in mines 'firedamp'.
In the 1800's it was used for streetlamps powered by sewer tanks under the streets. Needless to say there were frequent explosions.
Of course we've all heard about cow farts and as youngsters we lit our own farts with a lighter (yes, it did singe our asses). Gross I know, but we did it gleefully. All the uses of Methane!
Butane and propane are close cousins having two or three carbon atoms respectfully, bonded to hydrogen; Much less volatile than Methane.