I've put an arbitrary cut off date of pre-1950 on this list, which eliminates Bob Dylan and the Beatles although they will undoubtedly appear on a "Time Tested Songs" list in the future. There are many more songs that could be included, and I might make this a regular repeating feature in the NMW blog. This info comes from the invaluable Wikipedia website (special thanks to all the researchers).
"Hard Times Come Again No More" - written by Stephen Foster in 1859. According to Robert B. Waltz, it is the most popular Foster song with folk revival singers and wasn't especially popular at the time it was written. However, Stephen Foster himself considered it his own favorite of his songs. It has been recorded by Emmy Lou Harris, Nanci Griffith, Golden Palominos (Syd Straw) and many others.
"It's All in the Game"- Carl Sigman composed the lyrics in 1951 to fit a 1911 composition entitled "Melody in A Major," written by Charles Dawes, who would later become the Vice President of the United States under Calvin Coolidge. It is thus the only #1 pop single in history to have been co-written by a U.S. Vice President.
"Man of Constant Sorrow" - a traditional American folk song written originally by Dick Burnett, a blind fiddler from Kentucky. The song was originally recorded by Dick Burnett as "Farewell Song" printed in a Richard Burnett songbook, c. 1913.
"Someone to Watch Over Me" - composed by George Gershwin, with lyrics by Ira Gershwin from the musical Oh, Kay! (1926), where it was introduced by Gertrude Lawrence. It has been performed by numerous artists, such as Frank Sinatra, Linda Rondstadt, and Sting, and is a key work in the Great American Songbook.
"Frankie And Johnny" - The first published version of the music appeared in 1904, credited to and copyrighted by Hughie Cannon. The familiar "Frankie and Johnny were lovers" lyrics first appeared (as "Frankie and Albert") in On the Trail of Negro Folksongs by Dorothy Scarborough, published in 1925; a similar version with the "Frankie and Johnny" names appeared in 1927 in Carl Sandburg's The American Songbag. It has been recorded by artists as diverse as Johnny Cash, Jack Johnson, Louis Armstrong, Sam Cooke and none other than Elvis.
"Can the (Will The) Circle Be Unbroken (By and By)" is a well-known country/folk song reworked by A. P. Carter from a hymn by Ada R. Habershon and Charles Gabriel. It first appeared in the 1930s and has been recorded by hundreds of artists including Bill Monroe and the Nitty Gritty Dirt Band.
"This Land Is Your Land" - The lyrics were written by Woody Guthrie in 1940 in response to Irving Berlin's "God Bless America," which Guthrie considered unrealistic. Originally called "God Blessed America for Me", Guthrie varied the lyrics over time, sometimes including more overtly political verses than appear in recordings or publications. Guthrie lifted the melody note-for-note from "When the World's on Fire," a Baptist hymn recorded by country legends the Carter Family ten years earlier. However, some sources claim that a Carter Family original, "Little Darlin' Pal of Mine," was the source of the melody for "This Land."
"Rock Island Line" - Lead Belly (Huttie Ledbetter) and John and Alan Lomax supposedly first heard it from a prison work gang during their travels in 1934/35. Huttie finally settled on a format where he portrayed, in song, a train engineer asking the depot agent to let his train start out on the main line. While it is claimed that the song refers to the Chicago, Rock Island and Pacific Railroad, the song is considerably older than the first recording, and from some of the lyrics it can be interpreted that the "railroad" referred-to is actually the Underground Railroad, a slave escape route. It has been recorded by Bobby Darin, John Lennon, Johnny Cash, and Dan Zanes to name just a few.
"House Of The Rising Sun" - Like many classic folk ballads, the authorship of "The House of the Rising Sun" is uncertain. Folklorist Alan Lomax, author of the seminal 1941 songbook Our Singing Country, wrote that the melody was taken from a traditional English ballad and the lyrics written by a pair of Kentuckians named Georgia Turner and Bert Martin. Other scholars have proposed different explanations, although Lomax's is generally considered most plausible. It has ben recorded by The Animals, Frijid Pink, and Dave Van Ronk to name just a few.
"Sometimes I Feel Like a Motherless Child" - a traditional Afro-American spiritual. The song dates back to the era of slavery in the United States when it was common practice to sell children of slaves away from their parents. An early performance of the song dates back into the 1870s by the Fisk Jubilee Singers. Like many traditional songs, it has many variations and has been recorded widely by artists such as Richie Havens, Van Morrison, Hootie & The Blowfish and others.