Species (22.489)
- Favella franciscana Kofoid & Campbell 1929
- Favella helgolandica Brandt 1906
- Favella infundibulum Kofoid & Campbell 1929
- Favella markusovszkyi Daday 1887
- Fitoacineta periacinetoides Nozawa 1938
- Filiformis intermedium Hirshfield, Isquith & Bhandary 1965
- Flectacineta livadiana Mereschkowski ()
- Flectichona crenata Jankowski 1973
- Flectichona filicauda Jankowski 1973
- Foettingeria actiniarum Claparede 1863
- Foissnerides heliophagus Song & Wilbert 1989
- Folliculina similis Dons 1915
- Folliculina spirorbis Dons 1912
- Folliculina simplex Dons 1915
- Folliculina viridis Wright 1858
- Folliculina stylifera Wright 1858
- Frontonia branchiostomae Codreanu 1928
- Frontonia curva Fromentel 1876
- Frontonia depressa Stokes 1886
- Frontonia cypraea Zacharias 1904
- Frontonia elliptica Beardsley 1902
- Frontonia dubia Foissner 1980
- Frontonia elongata Burkovsky 1970
- Frontonia lurida Blochmann 1895
- Glaucoma dragescui Corliss 1971
- Glaucoma ficaria Kahl 1926
- Glaucoma flexile Penard 1922
- Glaucoma elongata Fromentel 1874
- Glaucoma gigantea Grandori & Grandori 1934
- Glaucoma frontata Stokes 1886
- Glaucoma laterimarginata Dumas 1930
- Glaucoma hyalina Wang & Nie 1932
- Glaucoma maupasi Kahl 1926
- Glaucoma limbata Dumas 1930
- Glaucoma macrostoma Schewiakoff 1889
- Glaucoma myriophylli Penard 1922
- Glaucoma parasiticum Penard
- Glaucoma rubescens Penard 1922
- Glaucoma reniforme Schewiakoff 1892
- Glaucoma sagitta Kahl 1926
- Glaucoma scintillans Ehrenberg 1830
- Glaucoma sphagni Penard 1922
- Glaucoma subrotondata Dumas 1930
- Glaucoma sinuosa Dumas 1937
- Glaucoma spumosa Penard 1922
- Glaucoma terricola Gellert 1957
- Glaucoma wrzesniowskii Mereschkowsky 1879
- Glaucomella sagitta Kahl 1926
- Glauconema trihymene Thompson 1966
- Glaucoma vorax Kidder, Lilly & Claff 1940
- Glossatella amoebae Grenfell 1884
- Glenotrochilia oliva Claparède & Lachmann 1859
- Glossa corsica Gourret & Roeser 1887
- Glossatella glabra Roth 1909
- Glossatella cotta Voigt 1902
- Glossatella piscicola Blanchard 1885
- Glossatella tintinnabulum Kent 1881
- Goniocoma macomae Chatton & Lwoff 1924
- Gonostomum affine Stein 1859
- Gonostomum algicola Gellert 1942
- Gonostomum andoi Shibuya 1929
- Gonostomum bryonicolum Gellert 1956
- Gonostomum ciliophorum Gellert 1956
- Gonostomum franzi Foissner 1982
- Gonostomum kuehnelti Foissner 1987
- Gonostomum pediculiformis Maupas 1883
- Gonostomum geleii Gellert 1957
- Gonostomum spirotrichoides Gellert 1956
- Gonostomum strenuum Engelmann 1862
- Gonzeela colonalis Kufferath 1953
- Gorgonosoma arbusculum Swarczewsky 1928
- Gorillophilus thoracatus Imai, ? 1991
- Grandoria aculeata Grandori & Grandori 1934
- Grossglockneria acuta Foissner 1980
- Frontonia vacuolata Dragesco 1960
- Frontonia vernalis Ehrenberg 1833
- Frontonia vesiculosa Cunha 1913
- Frontoniella complanata Wetzel 1927
- Frontoniella marina Roque 1961
- Fuscheria nodosa Foissner 1983
- Fuscheria marina Petz, Song & Wilbert 1995
- Fuscheria terricola Berger, Foissner & Adam 1983
- Gajewskajophrya melosirae Gajewskaja 1933
- Gargarius gagarius Chatton & Lwoff 1934
- Gargarius gargarius Chatton & Lwoff 1934
- Gassovskiella galea Gassovsky 1918
- Gastrocirrhus adhaerens Faure-Fremiet 1954
- Gastrochaeta fissa Dujardin 1841
- Gastrocirrhus intermedius Lepsi 1928
- Gastrocirrhus monilifer Ozaki & Yagiu 1942
- Gastrocirrhus stentoreus Bullington 1940
- Gastrocirrhus trichocystus Ito 1958
- Gastronauta membranaceus Engelmann in Bütschli 1889
- Loxophyllum dragescoi Carey 1992
- Helicoprorodon barbatus Dragesco 1954
- Helicoprorodon maximus Dragesco 1954
- Helicoprorodon minutus Bock 1952
- Helicoprorodon gigas Kahl 1933
- Helicoprorodon orientalis Raikov 1963
- Helicostoma marinum