• Styx N.J. Norton & J.W. Hall, 1967 † [Phylum: Sporae dispersae, Family: ]
• Styx Oppenheim, 1895 † (uncertain) [Phylum: Mollusca, Family: Mollusca (awaiting allocation)]
• Styx Staudinger, 1875 [Phylum: Arthropoda, Family: Riodinidae]
• Styx infernalis Staudinger, 1875
• Styxia Hull, 1943 (uncertain)
• Styxisporites I.C. Cookson & M.E. Dettmann, 1958 †
• Styxisporites linearis Cookson & Dettmann †
• Styxon Bleszynski, 1962
• Styxon ciniferalis Caradja, 1925
• Styxophrya Foissner, Moon-van der Staay, van der Staay, Hackstein, Krautgartner & Berger, 2004
• Styxorthis Mergl, 1991 †
• Styxosaurus Welles, 1943 †
• Styxowia Melnitsky & Ivanov in Kopylov et al., 2020 †