What One Learns from Other Instrumental Repertoire
The left hand (but, truly, your whole musicianship!) can benefit from setting aside some time to learn some passages of choice selected among the Partitas for Solo Cello by J. S. Bach.
Likewise, some unusual passages can be found for the right hand in the Flute Sonata in B Minor, BWV 1030 by Bach (in the flute part only), as well as other sonatas with flute by the same composer.
There are also a number of etudes for flute that would allow the right hand to get acquainted with unusual patters