It's often been said that Bob Dylan is an example of a mediocre singer who is one of the most accomplished talents of our time. There are many great songs in the 60s and 70s, including later, but not as many, made famous by other singers which had Bob Dylan as the songwriter. Dylan was a Jewish kid from Duluth, Minnesota who idolized the folk-music singer Woody Guthrie so much that at age 19, Dylan traveled to visit the extremely sick Guthrie who had Huntington's Disease. They became good friends and it's obvious from Dylan's earlier works how much Guthrie influenced him. Dylan's talent as a writer and a poet was inspired by Guthrie, but the talent was all Dylan's own. Despite a mediocre singing voice, his songs had resonance and not only invited hundreds of covers, but requests for his songwriting talents.
Even though Dylan sang several of his own songs, they were picked up by other artists and turned into classics. One of my favorites is Jimi Hendrix's "All Along the Watchtower"...a Dylan song which he recorded and released 6 months before the Hendrix version.
All Along the Watchtower - Wikipedia
"Forever Young" is usually known by other singers than Dylan even though it's his song and he recorded it first. I remember the Joan Baez version best, but it's been covered by a lot of people/bands.
Forever Young (Bob Dylan song) - Wikipedia
"Make You Feel My Love" is a 1997 song covered in 1998 by Garth Brooks (and reached #1 on the CW charts) and also by Adele in 2008.
Songfacts - Songs written by Bob Dylan