Johann Strauss Sr.'s Alexandra-Walzer is a classic mid-19th century Viennese ballroom waltz transcribed for piano. It features the characteristic lilt and melodic charm that made the Strauss family famous.
The wide-span left hand accompaniment requires flexibility to maintain the pulse without losing the lyrical flow of the melody.
Comparable difficulty and character — good candidates for what to learn next.
Alexandra-Walzer (Op.56) is rated Henle level 5 of 9 — late intermediate repertoire, roughly ABRSM grades 6–7. In the RCM system it corresponds to about level 7.
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 Alexandra-Walzer (Op.56) lasts about 5 minutes.
Alexandra-Walzer (Op.56) 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 Alice-Polka by Johann Strauss Sr., Beliebte Annen-Polka by Johann Strauss Sr., Brüder Lustig by Johann Strauss Sr. — see the full similar-pieces list on this page.