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](http://www.matias.ca/ergopro/programmable/).
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.