Leif is one of the most recognizable Scandinavian names, thanks to Icelandic explorer Leif Erikson, and is still one of the best, with a pleasant aural association with the word leaf.
Leif Erikson, son of explorer Eric the Red, was the first European to land in North America--some five hundred years before Columbus. Centuries later, the name became associated in the U.S. with 1970s teen idol Leif Garrett, the name peaking on the charts at Number 654 in 1970, dropping off completely in 1987. It climbed back onto the Top 1000, but just barely, in 2014.
Pronounced LAYF in its Scandinavian milieu, Leif and Lief are often pronounced as Leaf in this country. Joaquin Phoenix was for a time known as Leaf, in keeping with the nature names of his siblings.