Probably "Madame Bonaparte".
I've played it for years, it was the first piece I ever learned to play by ear. I've experimented with it, both right and left hands, used different speeds, every thing from slow air to breakneck, different rhythms. Just about every way you can butcher a tune I've butchered it over the years. It's one of my "go to " tunes if I'm trying out a new box.
Each time I play it anew I can learn something new from it.
Have you come across the northumbrian piper's variation sets? Billy Pigg's set is difficult beyond belief in places but the common one is approchable if you play it at a steady pace, it's also a lot of fun!
X:1
T:Madame Bonaparte
M:4/4
L:1/8
Q:1/4=150
R:Hornpipe
K:G
d>c|:B2 B>A B>dB>G|c2 c>B c>ec>A|G>Bd>f g>fg>e|d2-d>e d>cB>A|
B2 B>A B>dB>G|c>Bc>d e>fg>e|d>BG>B c>AF>A|1 G2 G>F G2 d>c:|2 G2 G>F G2 B>A|
|:G>Bd>f g>fg>e|d2-d>e d>cB>A|G>Bd>f g>fg>e|d2-d>e d>cB>A|
(3Bcd G>d B>dG>d|c>e A>e c>e A>e|B>dG>d B>dG>G|F>A D>A F>A (3d^c=c|
B>dG>d B>dG>B|c>Bc>d e>fg>e|d>BG>B c>AF>A|1 G2 G>F G2 B>A:|2 G2 G>F G2 (3d^c=c|
|:B2 B>A (3Bcd B>G|c2c>B (3cde c>A|(3GDG (3BGB (3dBd (3gfe|d2-d>e d>cB>A|
B2 B>A (3Bcd B>G|c>Bc>d e>f (3gfe|(3dBG (3DGB c>AF>A|1 G2 G>F G2 (3d^c=c:|2 G2 G>F G2 B>A|
|:G>B (3def g>a (3gfe|d2-d>e d>cB>A|(3GDG (3BGB (3dBd (3gfe|d2-d>e d>cB>A|
(3GBd (3gdB (3GBd (3gdB|(3Gce (3gec (3Gce (3gec|(3GBd (3gdB (3GBd (3gdB|(3Adf (3afd (3Adf (3afd|
(3GBd (3gdB (3GBd (3gdB|(3cGc (3ece (3gfg (3age|(3GBd (3GBd (3DFA (3DFA|1 (3GBd (3GBd g2 B>A:|2 (3GBd (3GBd g2 d>c|
Q:1/4=130
B2 B>A B>dB>G|c2 c>B c>ec>A|G>Bd>f g>fg>e|d2-d>e d>cB>A|
B2 B>A B>dB>G|c>Bc>d e>fg>e|d>BG>B c>AF>A|G2 (3gfa Hg2|
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