Here is a list of materials I use for solfege lessons. A few of the books are available online for free and the rest are available at very affordable prices. Please stay tuned for more content on this page! I am hoping to add more example videos, sample curricula, and more content shortly.
Georges Dandelot, Manuel Pratique
Pasquale Bona, Rhythmical Articulation
A. Dannhauser. Solfege des Solfeges Book 1 (Available free online)
A. Dannhauser, Solfege des Solfeges Book 1-3