Modern Hagiography
Lives of the Saints by Sabine Baring-Gould.
Pictorial Half Hours with the Saints by Auguste François Lecanu.
Roses of Martyrdom by C. M. Cresswell (pdf page 39).
Medieval Hagiography
The Life of Saint Pelagius of Cordoba translated into English is not available in open access.
Poem by Hrotsvitha (Latin with French translation)
Art & Architecture
Warburg Institute Iconographic Database
Guide to Christian Iconography: Images, Symbols, and Texts
The Saints in Art by Joseph Maria von Radowitz.
Emblems of Saints by Which They Are Distinguished in Works of Art by F. C. Husenbeth.