as a regular on the folk club circuit in the UK in the 60s i got to see a fair few of the big names of the folk boom - joni mitchell played one of the clubs i used to go to.

for trad folk songs two names i think you would like are Martin Carthy and Nic Jones. Martin Carthy apparently taught Paul Simon the riff to Scarborough Fair! He played as a duo with Dave Swarbrick on fiddle and later joined Steeleye Span. Nic Jones started in a trio called the Halliard but later went solo. He was the most amazing guitarist until a road accident.

Both of them are available on Amazon so I assume they'll be on spotify and similar. a good example of Nic Jones's guitar playing is 'Reynard the fox' on ballads and songs

the whole album is available here

https://www.youtube.com/watch?v=_kxbK46Ql8g

for the best folk rock album of all time try No Roses by Shirley Collins and the Albion Band. especially if you've never heard a flanged concertina!