• Thesea Duchassaing & Michelotti, 1860
• Thesea acanthoides (Thomson & Russell, 1909)
• Thesea alternata (Nutting, 1910)
• Thesea antiope Bayer, 1959
• Thesea bebrycoides (Nutting, 1910) accepted as Thesea acanthoides (Thomson & Russell, 1909)
• Thesea bicolor Deichmann, 1936
• Thesea boninensis (Aurivillius, 1931) accepted as Euplexaura boninensis (Aurivillius, 1931)
• Thesea campanulifera (Nutting, 1910) accepted as Discogorgia campanulifera (Nutting, 1910)
• Thesea citrina Deichmann, 1936
• Thesea crosslandi Hickson, 1928 accepted as Muricea fruticosa Verrill, 1869
• Thesea dalioi Breedy & Guzman, 2018
• Thesea dendritica (Nutting, 1910)
• Thesea echinata Tixier-Durivault, 1970 accepted as Thesea bicolor Deichmann, 1936
• Thesea exerta (Ellis & Solander, 1786) accepted as Thesea guadalupensis Duchassaing & Michelotti, 1864
• Thesea filiformis (Wright & Studer, 1889) accepted as Elasmogorgia filiformis Wright & Studer, 1889
• Thesea filigella (Thomson & Dean, 1931) accepted as Astrogorgia filigella (Thomson & Dean, 1931)
• Thesea flava Nutting, 1910 accepted as Pseudothesea flava (Nutting, 1910)
• Thesea flexilis Nutting, 1910 accepted as Pseudothesea flexilis (Nutting, 1910)
• Thesea gemmata Verrill, 1869 accepted as Swiftia exserta (Ellis & Solander, 1786)
• Thesea gracilis (Gray, 1868)
• Thesea gracilis Deichmann, 1936 (accepted > unreplaced junior homonym)
• Thesea grandiflora Deichmann, 1936
• Thesea grandiflora var. grandiflora Deichmann (uncertain > unassessed)
• Thesea grandiflora var. rugulosa Deichmann, 1936
• Thesea granulosa Deichmann, 1936
• Thesea guadalupensis Duchassaing & Michelotti, 1864
• Thesea hebes Deichmann, 1936
• Thesea immersa Nutting, 1910 accepted as Pseudothesea immersa (Nutting, 1910)
• Thesea mitsukurii (Kinoshita, 1909) accepted as Euplexaura mitsukurii (Kinoshita, 1909)
• Thesea nivea Deichmann, 1936
• Thesea nutans (Duchassaing & Michelotti, 1864) accepted as Caliacis nutans (Duchassaing & Michelotti, 1864)
• Thesea pallida Nutting, 1910 accepted as Pseudothesea pallida (Nutting, 1910)
• Thesea parviflora Deichmann, 1936
• Thesea placoderma Nutting, 1910 accepted as Pseudothesea placoderma (Nutting, 1910)
• Thesea plana Deichmann, 1936 accepted as Lytreia plana (Deichmann, 1936)
• Thesea pulchra (Nutting, 1910) accepted as Paraplexaura pulchra (Nutting, 1910)
• Thesea pyrrha Carpinelli, Cordeiro, Castro & Kitahara, 2022
• Thesea ramosa (Nutting, 1912) accepted as Elasmogorgia ramosa Nutting, 1912
• Thesea ramulosa (Gray, 1870) accepted as Echinogorgia ramulosa (Gray, 1870)
• Thesea reticuloides (Nutting, 1910) accepted as Paraplexaura reticuloides (Nutting, 1910)
• Thesea rigida (Thomson, 1927)
• Thesea rubra Deichmann, 1936
• Thesea rugosa Deichmann, 1936
• Thesea sanguinea Nutting, 1910 accepted as Echinogorgia sanguinea (Nutting, 1910)
• Thesea simplex Nutting, 1910 accepted as Pseudothesea simplex (Nutting, 1910)
• Thesea solitaria (Pourtalès, 1868)
• Thesea talismani Grasshoff, 1986
• Thesea umbraticoides (Studer, 1878) accepted as Muricella umbraticoides (Studer, 1878) accepted as Astrogorgia umbraticoides (Studer, 1878)
• Thesea variabilis (Studer, 1894)