‘Softly, As in a Morning Sunrise’ is a fun tune to rip on that’s most often been recorded in D minor (concert C). You can create a lot of tension and intensity over the A sections and use the bridge as a release. It’s a great melody and there’s a lot of good versions available on Youtube, Spotify, etcetera...Trane, Sonny (Rollins and Clark!), and several others.
And of course as mentioned you can always move any tune to a different key. Softly is actually a great song to work up in all keys because the melody isn’t that difficult to move around.