As above.
Most GMK sets come with (used to come with??) the basic ANSI full size layout and maybe half a dozen extras (1.5x Ctrl etc.).
This set allegedly covers ANSI, US-ISO, Winkeyless, 1800, 65%/75%/96-key, FC660, Minivan, JD40/45, Planck/Preonic, Minorca, HHKB, Atreus/62, and more.
That's a heck of a lot of extra keycaps that GMK wouldn't even have considered making a few years ago.