Found two more.

Highland Laddie and Can Ye Sew Cushions in Beethoven's 25 Schottische Lieder op. 108 -- no. 3 is Can Ye Sew Cusions and no. 7 is Highland Laddie.

Barry Taylor's versions of these Scottish folksongs are here

The Unheard Beethoven page (where you can hear no. 7, Bonnie Laddie, Highland Laddie) is here.

O Sweet Were the Hours (op. 108 no. 3) can be heard here.

I know there are more in opus 108, but I haven't listened to all of them yet -- these were just two that I recognized. (I heard O Sweet Were the Hours on the radio today - December 16 - Beethoven's birthday.)