piano chord
Gm7♭5
G1B♭♭3D♭♭5F♭7
A diminished triad with a minor seventh rather than a diminished one — half diminished, and not the same chord as dim7.
What is true of it
Gm7♭5 is G, B♭, D♭ and F — 1, b3, b5 and b7 counted from G.
These are also the notes of B♭m6/G and A♯m6/G. Which name is right depends on what is underneath and what came before — the notes alone do not decide.