What search term to use for "fat" keycaps?

I'm looking for "fat"? keycaps similar to what Matias uses for Esc, Ctrl, Option, Cmd and Space keys on their ErgoPro.
What search term should I use to find similar keycaps? I've tried "tall", "fat", "oversized", "big", etc., but I only find extra wide (in the X direction) or extra tall (in the Z direction) rather than in the Y direction.
Any help welcome.