Robert Schumann's Blumenstück Op. 19 is a series of linked episodes that drift through changing moods in a rondo-like fashion. It is noted for its delicate, atmospheric writing that avoids the bravura typical of the period.
The primary challenge is layering the textures to ensure the melody projects through the complex middle-voice accompaniment.
Comparable difficulty and character — good candidates for what to learn next.
Blumenstück Op.19 is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 8.
You should be comfortable at Henle level 5 — meaning you can already play level 4–5 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 Blumenstück Op.19 lasts about 3 minutes.
Blumenstück Op.19 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 Bilder aus Osten by Robert Schumann, 'Abegg' Variations Op.1 by Robert Schumann, Bajka by Stanisław Moniuszko — see the full similar-pieces list on this page.