Depending on the limitations, I for one am presently biased towards soulful songs with ethereal music like these oldies.

https://www.youtube.com/watch?v=9VDzhx0TB30

Who's Holding Donna Now (with Lyrics) - El DeBargeYouTube

https://www.youtube.com/watch?v=FlhMs4HZGU4

Show Me The Way - Styx | Lyrics | 1990YouTube

https://www.youtube.com/watch?v=5Kd58d5VgB8

Drive - The Cars (Lyrics)YouTube

Seem high to me:

https://www.youtube.com/watch?v=dNyIntYGBOw

KC and The Sunshine Band Please Don't GoYouTube

https://www.youtube.com/watch?v=1KPiElw6qy8

All ApologiesYouTube

https://www.youtube.com/watch?v=QdsWDpnR0BQ

ZZ Ward - Help Me Mama (Official Video)YouTube

And here's a YouTube mix that came up when I searched for soprano songs:

https://www.youtube.com/watch?v=3ECJ7jSsQws&list=RDQMWlVi_XNrTVg&start_radio=1

'Turn The Lights Off' by Tally Hall is so fun to sing :0

Or 'Ruler Of Everything' but one part is kinda hard to sing-

https://www.youtube.com/watch?v=dLrdSC9MVb4

Tally Hall - Turn The Lights OffYouTube

https://www.youtube.com/watch?v=I8sUC-dsW8A

Tally Hall - Ruler of EverythingYouTube

I forgot one >:)

https://www.youtube.com/watch?v=EOFA9kPQ_uU

Tally Hall - Hidden in the SandYouTube