Have you got Lucinda Geoghegan's 'Singing Games and Rhymes for the Early Years' and for 'Middle Years'? Also her 'Going for Bronze' book? There is quite a lot of material in there.
There's a good little canon you may not know - d rr mm s / ls mr m- /d rr mm s / ls mr d- // Words are Come, follow, follow me /Listen to my song /Come, follow, follow me /Echoing along// It is in 4/4 and works beautifully in canon 2 beats apart - both for singing and playing.
There is also some good pentatonic material in '150 American Folk Songs to sing, read and play', 'Sail Away' and 'How Can I Keep from Singing?' (all these available through the BKA website), also the two volumes of the Pentatonic Song Book by Brian Brocklehurst.
Hope this helps.