Another type of gas commonly used is petroleum gas, which is prepared by refining petroleum of wet natural gas. Petroleum gas is propane or butane.
Coal gas, which was manufactured from coal and largely consists of hydrogen, carbon monoxide and methane, is no longer manufactured or used.
Another type of gas that could be included in the category is biogas, which is a manufactured gas made from biological waste products, such as: manure, sewage, food waste and green waste. Biogas is predominantly methane.
US Energy Information Administration (type "other gases" in the search box)
Explained here in the footnotes
Other Gas includes blast furnace gas and other manufactured and waste gases derived from fossil fuels.
0.3% if anyone is interested. Prior to 2011 the definition of other gases was different.