Many are in fact common foundation deposits with pharaohs’ names. By contrast rare plaque cartouches have non royal titulature, see right example below. Period: since Dynasty 18 onwards
Blue and white glazed
plaque with the cartouche
of Amenhotep III
H 4.3, W 2.0, T 0.7
New Kingdom Dynasty 18
© 1998 Musée du Louvre/
Georges Poncet #E 3043
Blue glazed cartouche
of Shabako with sun disc
and plumes H 2.5, W 1.0
Kushite Dynasty 25
© 2017 University College
London
LDUCE-UC #13140
Green glazed steatite
double-sided cartouche
with ankh, nefer and neb
signs Early Dynasty 18
L 1.4, W 0.9, T 0.4
MET #36.3.41