Sulfur is commonly found in volcanic regions, southern deserts, lava islands, and the lower-left islands of some maps; look for small, bright yellow, orange, or cheese-like rocks rather than large rocks associated with golems. Mine these deposits with a pick or mining drill, and consider checking around wyvern caves, where defeating wyverns can also provide sulfur while offering access to eggs. Watch for hostile creatures such as wyverns, deathworms, and other desert threats, and remember that sulfur can also be used as food for baby magmasaurs.