The concave sundials found in ancient Egypt from the Greco-Roman period onwards are all of the types we see elsewhere in the Greco-Roman world. They are not, in the strictest sense "ancient Egyptian", but are included here for completeness. They include two objects found outside the boundaries of modern Egypt.
Within this category, there are two basic types of sundial, conical or spherical, depending on the shape of the shadow-catching surface. Conical dials are much better represented in the archaeological record as it currently stands.
Objects
Conical sundials:
SC Basa: Concave Sundial from Basa
SC BM 1936,0309.1: Concave Sundial BM 1936,0309.1 in London
SC BM EA68475: Concave Sundial EA68475 in London
SC BAAM 0235: Concave Sundial BAAM 0235 in Alexandria
SC GRM 17483: Concave Sundial 17483 in Alexandria
SC GRM 19810: Concave Sundial 19810 in Alexandria
SC NMWarsaw 198850: Concave Sundial 198850 in Warsaw
SC Petrie UC16500: Concave Sundial UC16500 in London
SC Petrie UC36147: Concave Sundial UC36147 in London
SC SNM 34605: Concave Part of Double Sundial SNM 34605 in Khartoum from an-Naq'a
Conical variant sundial:
SC Fitz GR.100.1906: Concave Sundial GR.100.1906 in Cambridge
Spherical sundial:
SC BM 1909,0216.10: Concave Sundial 1909,0216.10 in London
Sundials of indeterminate type:
SC BM EA68817: Concave Sundial EA68817 in London
SC GRM 15735: Concave Sundial 15735 in Alexandria