you may have heard something from the album
Gling-Gló, which is pure jazz, though it has no guitar in it...
Gling-Gló - Wikipedia, the free encyclopedia
a few singles from Debut have b-sides feature guitar (tracks like Stigdu Mig and Síðasta Ég), but they're not particularly jazzy.
So Broken from Homogenic has guitar, but it's Spanish, not jazz...
hard to say! she's got a
big discography. any other info you remember would help a lot