Most Helpful Guy
Jim Croce is the fucking man, I'd start anyone interested in him off with 'I have to say I love you in a song', 'I got a name', & 'time in a bottle'
Terry Callier is kind of a romance, sub-gospel kind of singer I like. His good ones would be 'Paris blues', 'ordinary joe', & 'dancing girl'. A lot of his songs are pretty smooth.
Afrobeat artist Fela Kuti has some boisterous songs but I think 'Sorrow Tears & Blood' is a song that's smooth enough to bump to while stoned.
Wang Changyuan is a chinese artist whose songs are entirely instrumental, for most of them. They're often though provoking & easy to relax to in the background.