"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.