Aleksandr Ilyinsky’s 'Butterfly' is a well-known encore piece that captures the light, ethereal quality of its subject through delicate passagework. It stands out for its evocative use of chromaticism within a Romantic harmonic framework.
Master the delicate balance of the flowing sixteenth notes so they remain transparent and airy rather than muddy.
Comparable difficulty and character — good candidates for what to learn next.
Butterfly is rated Henle level 4 of 9 — intermediate repertoire, roughly ABRSM grades 5–6. In the RCM system it corresponds to about level 7.
You should be comfortable at Henle level 4 — meaning you can already play level 3–4 pieces cleanly. Learning it one level early is possible as a stretch piece, but more than that usually leads to months of frustration.
A typical performance of Butterfly lasts about 3 minutes.
Butterfly is available as free public-domain sheet music on IMSLP — the score is linked directly from this page.
Pieces at a comparable difficulty and character include Berceuse by Aleksandr Ilyinsky, Boléro by Charles Gounod, Piano Sonata No. 11 in A major by Wolfgang Amadeus Mozart — see the full similar-pieces list on this page.