Public Domain Scores:

Robert Schumann, Album for the Young

http://vmirror.imslp.org/files/imglnks/usimg/0/00/IMSLP00668-Schumann_-_Album_for_the_Young,_Op_68.pdf

Pyotr Tchaikovsky, Album for the Young

http://vmirror.imslp.org/files/imglnks/usimg/b/b5/IMSLP07996-Tchaikovsky_-_Op.39_-_Album_for_the_Young.pdf

Tchaikovsky, 12 Pieces, Op. 40

http://vmirror.imslp.org/files/imglnks/usimg/3/3e/IMSLP280373-SIBLEY1802.19359.8e39-39087012739217score.pdf

Franz Schubert, Various Dances/Waltzes

http://vmirror.imslp.org/files/imglnks/usimg/a/a6/IMSLP37831-PMLP07869-Schubert_Taenze_Universal_Op_18_600dpi.pdf

Frédéric Chopin, Waltzes

http://vmirror.imslp.org/files/imglnks/usimg/e/ef/IMSLP599312-PMLP964055-Chopin_Valzer_Brugnoli.pdf

Chopin, Mazurkas

http://vmirror.imslp.org/files/imglnks/usimg/5/53/IMSLP391046-PMLP318858-Chopin_-_Mazurkas_-_Edition_Durand_-_Editor_Debussy.pdf

Johannes Brahms, Waltzes Op. 39 (simplified version)

http://vmirror.imslp.org/files/imglnks/usimg/5/5a/IMSLP13155-Brahms_op039_Waltzes_(simplified).pdf

Enrique Granados, Eight Poetic Waltzes

http://vmirror.imslp.org/files/imglnks/usimg/e/e4/IMSLP08872-Granados_8_Valses_poeticos.pdf

Brahms, Hungarian Dances

http://vmirror.imslp.org/files/imglnks/usimg/3/38/IMSLP110610-PMLP16016-JBrahms_Hungarian_Dances,_WoO1_solo_edSJ.pdf

Moritz Mozkowski, 5 Spanish Dances, Op. 12

http://vmirror.imslp.org/files/imglnks/usimg/b/ba/IMSLP18924-PMLP07167-Moszkowski_op.12_Spanische_T%C3%A4nze_2hands.pdf

Johann Strauss, Gems of Strauss

http://vmirror.imslp.org/files/imglnks/usimg/d/de/IMSLP294855-SIBLEY1802.22976.f418-39087012853968score.pdf

Tchaikovsky/Tanayev, Nutcracker

http://vmirror.imslp.org/files/imglnks/usimg/8/86/IMSLP30803-PMLP08586-Tchaikovsky-Op71PRtan.pdf

Tchaikovsky/Kashkin, Swan Lake

http://vmirror.imslp.org/files/imglnks/usimg/3/32/IMSLP17426-Tchaikovsky-Op20prKashkin.pdf

Ludwig Minkus, Don Quixote

http://vmirror.imslp.org/files/imglnks/usimg/8/84/IMSLP30799-PMLP65356-Minkus-DonQuixotePRmuz.pdf

Useful Scores to Purchase:

Dennis Agay, The Joy of Ballet Music https://www.amazon.com/Joy-Ballet-Music-Piano-Solo/dp/0825680352

Agay, The Joy of Waltzes, Tangos, and Polkas https://www.amazon.com/Joy-Waltzes-Tangos-Polkas-Piano/dp/0825681030

Hal Leonard, World's Great Classical Music Series, Opera's Greatest Melodies https://www.amazon.com/Operas-Greatest-Melodies-Selections-Classical/dp/0634005545

Genres/Forms to Explore:

Popular Music

Broadway Music

Polkas

Ragtime