The 0x33.board supports various different isomorphic keyboard layouts based on hexagonal grids. The current layout and the note to start the scale with in the bottom-left corner of the main grid can be set in the settings screen.
wicki/hayden
The Wicki/Hayden Note Layout is an isomorphic note layout conceived and independetly rediscovered in 1896 and 1986 respectively. The intervals between neighbouring keys are 2, 5 and 7 semitones, arranged such that a whole-tone scale lies horizontally along rows. The keys of an octave repeat vertically every second row.
jankó
The Jankó keyboard was designed in 1882. Neighbouring keys are 1 or 2 semitones apart and arranged such that keys that are on a vertical line correspond to the same note.
harmonic table
The Harmonic Table note-layout is known since at least the 18th century. The intervals between keys are 3, 4 and 7 semitones.
gerhard
I can’t find much on the name and origin of the Gerhard layout. Neighbouring keys are 1, 3 or 4 semitones apart.