Amazon Resources for Voice and Piano

There are many editions of the Singers Musical Theatre Anthology for all voice types.

There are many levels of the Royal Conservatory Celebration Series Piano Books.

Only one edition of each is included for reference.

Sight Singing - Concone

Sight Singing - Dannhauser

Sight Singing - Dannhauser

Accompaniments - Apps and Sites

Appcompanist.com
PianoTrax.com
youraccompanist.com
mypianoaccompaniment.com

Also check YouTube for karaoke tracks and many versions of accompaniments for the Vaccai exercises.

Scribd.com
A wonderful monthly subscription resource full of sheet music, audiobooks, reading materials. Lots to explore.