Something around that difficulty? Look at Rach Etudes Op 33 in Eb major, and Eb minor (the numbering can follow two systems, didn't wanna create confusion, look at the key signature)
Rach preludes: C minor, C major, Eb minor, etc.
Chopin Etudes: Nearly all of them...
Liszt first TE.
Chopin preludes: Bb minor, Eb major, G# minor, Eb minor, G major (might need to pair some up, their like 1 second long

)
Flight of the Bumblebee always does the trick
Also some Kapustin Jazz Preludes... some are amazing
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I played the Rach Eb major etude as a finale for a concert w/ a couple other people, and trust me, it does the trick.