There are hundreds of folksongs that are pentatonic. A pentatonic scale having 5 notes can come in many varieties.... It can be based on do: do re mi so la It can have the same notes but be extended by having a "so or la" below do, or a high "do", an octave above. ie: Great Big House in New Orleans ie: (extended Do pentatonic) Cumberland Gap, Little Black Bull, The Devil's Questions...

Then you can also have pentatonic scales ending (and or starting on): re: (has the same do re mi so la but "re" is the tonic) ie. "Shady Grove" is "re pentatonic" (if it had a "fa or ti" it would be in the Dorian mode)

So pentatonic: same as above (with fa or ti it would become Mixolydian) ie. "The Darby Ram"

La pentatonic: same as above (with fa or ti it would become Minor) ie. The Bird's Courting Song (Leatherwinged Bat)

Pentatonic scales based on "fa and mi" are much more rare in American folk music.

I collect folksongs according to these particular scales and use them as the basis for teaching in my music classroom (using the Kodaly approach). There are many books that sort folksongs and give a quick reference for pentatonic songs. If you are interested in songs that can be used for children that are pentatonic, let me know, and I can direct you to some good books.