• Monstrilla Dana, 1849-1852
• Monstrilla albatrossi Suárez-Morales, 2022
• Monstrilla anglica Lubbock, 1857
• Monstrilla angustipes (Isaac, 1974) accepted as Monstrillopsis angustipes Suárez-Morales, Bello-Smith & Palma, 2006
• Monstrilla annulata Suárez-Morales, 2024
• Monstrilla arctica Davis & Green, 1974 accepted as Caromiobenella arctica (Davis & Green, 1974)
• Monstrilla armoricana (Hesse, 1868)
• Monstrilla bahiana Suárez-Morales & Dias, 2001
• Monstrilla barbata Suárez-Morales & Gasca-Serrano, 1992
• Monstrilla bernardensis (Willey, 1920) accepted as Monstrillopsis bernardensis (Willey, 1920)
• Monstrilla boxshalli (Suárez-Morales, 1993) accepted as Cymbasoma boxshalli (Suárez-Morales, 1993)
• Monstrilla brasiliensis Dias & Suárez-Morales, In: Suárez-Morales & Dias, 2000 accepted as Caromiobenella brasiliensis (Dias & Suárez-Morales, In: Suárez-Morales & Dias, 2000)
• Monstrilla brasiliensis Suárez-Morales & Dias, 2000 accepted as Caromiobenella brasiliensis (Dias & Suárez-Morales, In: Suárez-Morales & Dias, 2000)
• Monstrilla brevicornis Isaac, 1974
• Monstrilla bullata (Scott A., 1909) accepted as Cymbasoma bullatum (Scott A., 1909)
• Monstrilla canadensis McMurrich, 1917 accepted as Caromiobenella helgolandica (Claus, 1863)
• Monstrilla capitellicola Hartman, 1961 (uncertain > nomen dubium)
• Monstrilla careli Suárez-Morales & Dias, 2000
• Monstrilla careloides Suárez-Morales, 2001
• Monstrilla caromiobenelloides Suárez-Morales & McKinnon, 2025
• Monstrilla chetumalensis Suárez-Morales & Castellanos-Osorio, 2019
• Monstrilla ciqroi (Suárez-Morales, 1993)
• Monstrilla claparedei (Giesbrecht, 1892) accepted as Cymbasoma claparedei (Giesbrecht, 1892)
• Monstrilla clavata Sars G.O., 1921 accepted as Monstrilla longicornis Thompson I.C., 1890
• Monstrilla conjunctiva Giesbrecht, 1902
• Monstrilla cymbula Scott A., 1909
• Monstrilla danae Claparède, 1863 accepted as Thaumaleus thompsoni Giesbrecht, 1893 represented as Cymbasoma thompsoni (Giesbrecht, 1893) represented as Cymbasoma thompsonii (Giesbrecht, 1893)
• Monstrilla dubia Scott T., 1904 accepted as Monstrillopsis dubia (Scott T., 1904)
• Monstrilla elongata Suárez-Morales, 1994
• Monstrilla filogranarum (Malaquin, 1901)
• Monstrilla fisgata Suárez-Morales & McKinnon, 2025
• Monstrilla floridana Davis, 1949
• Monstrilla fosshageni Suárez-Morales & Dias, 2001 accepted as Monstrillopsis fosshageni Suárez-Morales & Dias, 2001
• Monstrilla frondipes (Isaac, 1975) accepted as Cymbasoma frondipes Isaac in Grygier & Suárez-Morales, 2018
• Monstrilla germanica (Timm, 1893) accepted as Cymbasoma germanicum (Timm, 1893)
• Monstrilla ghardaqana (Isaac, 1975) accepted as Cymbasoma ghardaqanum (Isaac, 1975)
• Monstrilla ghardaquensis Al-Kholy, 1963 (unaccepted > nomen nudum)
• Monstrilla ghirardellii Suárez-Morales, Goruppi, de Olazabal & Tirelli, 2017
• Monstrilla gibbosa Suárez-Morales & Palomares-García, 1995
• Monstrilla gigas (Scott A., 1909) accepted as Cymbasoma gigas (Scott A., 1909)
• Monstrilla globosa Suárez-Morales, 2003
• Monstrilla gohari Al-Kholy, 1963 (unaccepted > nomen nudum)
• Monstrilla gracilicauda Giesbrecht, 1893
• Monstrilla grandis Giesbrecht, 1891
• Monstrilla grygieri Suárez-Morales, 2000
• Monstrilla hamatapex Grygier & Ohtsuka, 1995 accepted as Caromiobenella hamatapex (Grygier & Ohtsuka, 1995)
• Monstrilla helgolandica Claus, 1863 accepted as Caromiobenella helgolandica (Claus, 1863)
• Monstrilla hendrickxi Suárez-Morales & Velázquez-Ornelas, 2024
• Monstrilla humesi Suárez-Morales, 2001
• Monstrilla huysi Suárez-Morales & McKinnon, 2025
• Monstrilla ilhoii Lee, J. & Chang, 2016
• Monstrilla inserta Scott A., 1909
• Monstrilla intermedia Aurivillius accepted as Monstrilla longicornis Thompson I.C., 1890
• Monstrilla intermedia Krichagin, 1877 (unaccepted > nomen nudum)
• Monstrilla investigatoris Sewell, 1949
• Monstrilla janetgrieveae Suárez-Morales & McKinnon, 2025
• Monstrilla javensis Isaac, 1974 accepted as Cymbasoma javense Suárez-Morales, in Grygier & Suárez-Morales, 2018
• Monstrilla lata Desai & Bal, 1962
• Monstrilla latisetosa Suárez-Morales & McKinnon, 2025
• Monstrilla leucopis Sars G.O., 1921
• Monstrilla longa (Isaac, 1974)
• Monstrilla longibrachiata Suárez-Morales & McKinnon, 2025
• Monstrilla longicornis Thompson I.C., 1890
• Monstrilla longipes Scott A., 1909 accepted as Maemonstrilla longipes (Scott A., 1909)
• Monstrilla longiremis Giesbrecht, 1893
• Monstrilla longispinosa Bourne, 1890 accepted as Cymbasoma longispinosum (Bourne, 1890)
• Monstrilla longissima Krichagin, 1877 accepted as Monstrilla longispinosa Bourne, 1890 accepted as Cymbasoma longispinosum (Bourne, 1890)
• Monstrilla mahahualensis Suárez-Morales, 2022
• Monstrilla malaquini (Caullery & Mesnil, 1914) accepted as Cymbasoma malaquini (Caullery & Mesnil, 1914)
• Monstrilla mammillata Suárez-Morales & McKinnon, 2025
• Monstrilla mariaeugeniae Suárez-Morales & Islas-Landeros, 1993
• Monstrilla marioi Suárez-Morales, 2003
• Monstrilla minuta Isaac, 1975
• Monstrilla mixta Scott T., 1914
• Monstrilla nasuta Davis & Green, 1974
• Monstrilla nicholsii Davis, 1949
• Monstrilla obesa Isaac, 1975
• Monstrilla orcula Scott A., 1909
• Monstrilla ostroumovi Karavaev, 1895 accepted as Cymbasoma rigidum Thompson I.C., 1888
• Monstrilla ostroumowi Karavaev, 1894 accepted as Monstrilla rigidum Thompson I.C., 1888 accepted as Cymbasoma rigidum Thompson I.C., 1888
• Monstrilla pallida (Isaac, 1974) accepted as Cymbasoma pallidum (Isaac, 1974)
• Monstrilla papilliremis Isaac, 1975
• Monstrilla parki Suárez-Morales & McKinnon, 2025
• Monstrilla patagonica Suárez-Morales, Ramírez & Derisio, 2008 accepted as Caromiobenella patagonica (Suárez-Morales, Ramírez & Derisio, 2008)
• Monstrilla pileata Suárez-Morales & McKinnon, 2025
• Monstrilla pontica Krichagin, 1877 (uncertain)
• Monstrilla pseudograndis Zhou, Lian & Tan, 2025
• Monstrilla pustulata Suárez-Morales & Dias, 2001
• Monstrilla pygmaea Suárez-Morales, 2000 accepted as Caromiobenella pygmaea (Suárez-Morales, 2000)
• Monstrilla quadridens (Davis, 1947) accepted as Cymbasoma quadridens Davis, 1947
• Monstrilla quadriseta Davis, 1949 (unaccepted > nomen nudum)
• Monstrilla quintanarooensis (Suárez-Morales, 1994) accepted as Cymbasoma quintanarooense (Suárez-Morales, 1994)
• Monstrilla rebis Suárez-Morales, 1993
• Monstrilla reidae Suárez-Morales, 1993
• Monstrilla reticulata Davis, 1949 accepted as Monstrillopsis reticulata (Davis, 1949)
• Monstrilla rigidum Thompson I.C., 1888 accepted as Cymbasoma rigidum Thompson I.C., 1888
• Monstrilla roscovita (Malaquin, 1901) accepted as Cymbasoma roscovita (Malaquin, 1901)
• Monstrilla rostrata (Scott T., 1904) accepted as Cymbasoma rostratum (Scott T., 1904)
• Monstrilla rugosa Davis, 1947
• Monstrilla satchmoi Suárez-Morales & Dias, 2001