This package comes installed with the Latido app and features melodies and rhythms from Benjamin Crowell's Eyes and Ears anthology.
Download this and customize it to create your own module.
A large selection of easy melodies, mostly in C Major from a 1909 Sight Singing book. (Public Domain)
PDF is available here: archive.org
A large collection of melodies which progress from late beginner to intermediate, with some chromaticism, from a 1911 Sight Singing book. (Public Domain)
PDF is available here: IMSLP