Verified answer

If you really have a powerful voice these -

Beautiful - Christina Aguilara

Haven't Seen the Last of Me - Cher

Mean - P!nk

I Have Nothing - Whitney Houstin

Enough is Enough - Donna Summer

Give Your Heart A Break-Demi Lovato

Let The Flames Begin-Paramore

I Wasn't Prepared-Eisely

Love On Top-Beyonce

Safe And Sound-Taylor Swift <-- Not a very powerful song but its beautiful

Sally's Song-Evanescence

Monster-Paramore

Jar Of Hearts-Christina Perri

Some of these arent that powerful but there sorta difficult to sing.

Breakaway by Kelly Clarkson

Nothing Takes The Place Of You, by Asleep at the Wheel.