Underestimated, song, artist or group '' gems'' ?

I must have been waiting for this thread! These are songs/pieces that can move me. Here's my list:

FOLK
Most of Stan Rogers (folk category):
Album - 'Fogarty's Cove' / Songs - "Fisherman's Wharf", "The Wreck of the Athens Queen"
Album - 'Between the Breaks (Live)' / Songs - "Barrett's Privateers", "Witch of the Westmorland" & "The Mary Ellen Carter"

Judy Collins: Songs "Sunny Goodge Street" & "I Think It's Going To Rain Today"

Pentangle: Song "The Trees They Do Grow High"

Leo Kottke: particularly the albums "6 & 12-String Guitar" & "One Guitar, No Vocals"

ROCK
J.J. Cale:
Album - 'Special Edition' (best songs) / All especially songs "Crazy Mama", "Lies" & "Don't Cry Sister"

Robbie Robertson: 1st Album S/T

CSN &Y on '4-Way Street' - "Cowgirl in the Sand"

Quicksilver Messenger Service: Albums - either 'Happy Trails" or 'Sons of Mercury' (Greatest Hits)

It's A Beautiful Day: Song "White Bird"

CLASSICAL
Jussi Bjoerling & Robert Merrill - "Au Fond du Temple Saint" (duet from Bizet's 'The Pearl Fisher')

Bach - Concerto for Two Violins (Heifetz) RCA

Jean-Pierre Rampal/Lily Laskine - Japanese Melodies (maybe the most relaxing music I've heard)

COUNTRY
Don Williams: Song "Good Ole Boys Like Me"

Charlie Pride: Song "Roll On Mississippi"

That's a start...

October Project: Intense, sincere female vocals
Sunday's "Blind": Exceptional rock energy (forget sequals)
Batdorf & Rodney: Solid writing/performance. Usurped in "Steven Stills wannabe" critics purge.
Dust "Hard Attack": So-so production stunted their career -should have been Valhalla's house band.
Todd Rundgren: Anything after "Hello It's Me". Everything great up to "Second Wind". Known as "Musician's musician".

Jade Warrior "kites"
Bruce Cockburn "High Winds White Sky" "In the Falling Dark" "Humans" "Joy will find a Way"
Happy the Man
on ECM: Steve Tibbits "Safe Journey" Terje Rypdal "Decendre" Kenny Wheeler "Knu High" Ralph Towner "Solo Concert"
Oregon on Electra, "Roots in the Sky" in my opinion one of their best but a poor quality U.S. pressing, I never see it on import vinyl.

Mickey Newberry - Frisco Mabel Joy
Folks have recorded over 400 covers of his songs. This album is heartbreaking. I've loved it for 30 years.

I second J.J. Cale and The String Cheese Incident.