The 2001 soundtrack beat out U2 and Bob Dylan for the best-album Grammy and sold 7.6 million copies with almost no radio support, USA Today reported.
Its old-timey tunes sung by country, bluegrass performers brought new focus to artists such as Ralph Stanley and virtually created the niche of the Americana music radio format overnight.
The deluxe reissue includes a second disc of 14 tracks including 12 previously unreleased ones with the Kossoy Sisters' "I'll Fly Away" and the Cox Family's "In the Highways" in the mix, the newspaper said.
The collection was produced by veteran musician T Bone Burnett who saw the movie as a way to widen the appeal of roots music.
And there's a lot more music recorded by Alison Krauss, the late John Hartford, James Carter, Dan Tyminski, Gillian Welch and The Whites available to be released, Burnett said.
"That community came together with absolute generosity," Burnett said. "Those cats play all the time, and we never stopped recording."