Energy commodities are the commodities that fuel every aspect of modern life for humans, including things like cooking, heating, and transportation. These commodities include brent and WTI oil, natural gas, gasoline, and coal. Oil is by far the most traded energy commodity, with the largest marketplace being the New York Mercantile Exchange (NYMEX).
Many regulated forex brokers today offer at least a few energy commodities for trading as contracts-for-difference, better known as CFDs. This makes it easy to take leveraged positions on these commodities, with much lower margin requirements than what is common if you were to trade directly in the futures market.