For beginners:
1. Laura Shur - Tunes for three (for six hands , one piano) - Five extremely easy pieces for beginners. This is clearly pedagogical material. All parts similar difficulty. I cannot say I am too impressed. (I am not sure, but I believe there is a second volume).
Much better is:
2. Giovanni Piazza - 10 easy pieces for piano six hands ("Drei Mal zwei - Tre per due" - Schott). The first piece is a nice arrangement of twinkle twinkle little star. It then progresses through several different music styles (minimalist music, jazz, rock, but mixed up with classical styles: for instance there is a "blues"-fughe, the rock is a rock-passacaglia, and so on).
3. Pinwheels - Katherine Beard
4. Manfred Schimitz - Serenades for Six Hands (Mel Bay) - 13 piano pieces for six hands for young beginners. Especially appropriate for music instruction.
Intermediate:
1. "Klavierspiel zu drift". (Schott) - A collection (organized by Franzpeter Goebels) of pieces for 6 hands in three volumes: Most of the pieces are originally solo piano pieces (from the likes of Mendelssohn, Bach, etc.) arranged for six hands.
2. C. Gurlitt - Six Pieces for Six Hands; edited by Weekley & Arganbright. Special edition for one piano, six hands.
3. Stephen Yarbrough - Romp Ala Mozart for one piano, six hands. Myklas Music Press
4. Joyce Grill - Three's A Crowd Rag for One Piano, Six Hands (Warner Brothers.)
5. Christopher Norton - Microjazz piano trios (Boosey & Hawkes) - Easy pieces in popular styles such as jazz, blues, rock 'n' roll and reggae for three piano players (one piano six hands).
4. Also have a look here:
https://www.sibeliusmusic.com/cgi-bin/show_score.pl?scoreid=33418“Heroes of mine” A very nice piece by Bernard Hughes (no relation) which you can print.
https://www.sibeliusmusic.com/cgi-bin/show_score.pl?scoreid=30298Phillip Butall – “Three is company” (You will have to pay for this one).
Advanced: (Not that difficult since it is shared amongst six hands).
1. Percy Grainger – Zanzibar boat song (for one piano, 6 hands) (Schott).
2. Rachmaninoff – Besides “Romance” that Nana suggested above, there is also “Waltz” (Russian State Music Publishing – in one volume all of Rach’s duets as well)
3. Arthur Levering - Uncle Inferno for piano, 6 hands (7:00)Wonderful piece, it received the 1990 Composers Guild First Prize (music for children). You can listen to it (and order) here:
https://www.arthurlevering.com/music.html4. You can order the pieces below from the Lithuanian Publishing centre:
https://www.mic.lt/index2.htmlValentinas Bagdonas (1929) - Polyphonic Sonatine 1981 - 8'
Sonata – 1993 - 11'
Two Moods – 1993 - 12'
Festive Prelude – 1995 - 8'
Quasi tango – 1995 - 10'
Vytautas Barkauskas (1931) - Divertimento op.101 – 1993 - 4'
Zita Bruzaite (1966) - House of Rain – 2002 - 2'30
Vytautas Mikalauskas (1930) - Snow White and the Seven Dwarves – a cycle of 8 pieces for piano two, four, six hands - 1997-2000 - 15
Flower Suite - 1996-2001 - 20'
4. A collection of 13 pieces by several obscure American composers arranged for 6 hands by Julius Muller all downloadable:
https://memory.loc.gov/cgi-bin/query/r?ammem/mussm:@field(SUBJ+@band(Piano+music++6+hands++))
Just the tip of the iceberg, but this should get you started.
Best wishes,
Bernhard.