Here's a few, maybe lesser-known but great...

'Distant Melody' from the musical 'Peter Pan' - just lovely. A favorite of mine.

'Can't Help Singing' from the Deanna Durbin movie of the same name.

'Sing As You Work' - a real fun toe-tapping number from the movie 'Romance On the Range.'

'Who's Gonna Help Me Sing?' - a spiritual-style piece from the movie 'Heart of the Golden West.'

'Swing Me An Old-Fashioned Song' - fun number from the Shirley Temple film 'Little Miss Broadway.' Several quotes from traditional songs in this one.

In musicals, 'The Sound of Music' and 'Do-Re-Mi' are always the top...then there's Irving Berlin's 'Let Me Sing And I'm Happy,' and also 'Swing' and 'The Wrong Note Rag' from the musical 'Wonderful Town.'

I know I'll think of more later...I like this subject!