Category:Fictional elements introduced in 1921

• 1912
• 1913
• 1914
• 1915
• 1920
• 1921
• 1922
• 1924
• 1928
• 1929
• 1930

• 1870s
• 1880s
• 1890s
• 1900s
• 1910s
• 1920s
• 1930s
• 1940s
• 1950s
• 1960s
• 1970s