Man, we roleplayers just love our goblins, apparently. This one doesn't have you playing as the little monsters, though, and instead puts you against them (as nature intended!).
At 57 pages, The Burning Goblins is longer than many paid adventures, and it has a bunch of fabulous advice for new DMs. Best of all, you don't have to pick between systems, as this adventure is compatible with both Pathfinder and D&D 5th Edition.