"Good" songs and "popular" songs are often not the same. XD Sorry, but modern music (at least in America) isn't very good.
All the music I have to suggest isn't in English.
Here's a song that's in Japanese, covered by a Nico Nico Douga singer called Valshe. She's quite popular for her boyish type voice, which is why she does so many covers of a shouta-type character called Len.
You could sing anything by Valshe. She has a very low voice so you could probably match her pitch in almost any one of her songs. You could sing Halo by Beyonce, In Your Eyes by Onew, U by Taemin, or Hello by Nu'est.
Battlefeild- Jordan Sparks. For some people might sing this and sound like there voice is really tight and strained during the chorus. So sing this to someone and then have them tell you have they feel you sound.