Lives of the Saints by Alban Butler.
Lives of the Saints by Sabine Baring-Gould.
Our Birthday Bouquet Culled from the Shrines of the Saints and the Gardens of the Poets by Eleanor C. Donnelly.
Pictorial Half Hours with the Saints by Auguste François Lecanu.
Her lives are not in the public domain.
Nor is the Deeds of the Saxons, which also covers her life.
Art & Architecture
Quedlinburg Abbey (see also)
Warburg Institute Iconographic Database
Lives and Legends of the English Bishops and Kings, Mediaeval Monks, and Other Later Saints by Mrs. Arthur Bell.
The Saints in Art by Joseph Maria von Radowitz.