It has been previously demonstrated (pg. 46 Spanish Ballad, pg. 113 Right Hand Studies, pg. 116 Ascending Full Bar Study, pg. 128 Study in E minor) that pieces with a consistent chord structure, once memorised, can be used to provide variations for the right hand, both in fingerings and rhythmic structure.
An excellent example is the following Study in A minor by Aguado, which was originally written as an arpeggio study as seen below in Var. 1. For the sake of this exercise, it has been written as block chords to be memorised before studying the variations.
Pieces such as this provide great value due to the fact that so much variation can immediately be applied to one memorised piece, rather than learning several similar pieces.