"The arrangement follows loosely the characteristic of the regular periodic table: tools with similar functions in each column, getting heavier as you move down the rows."[1]

I can see perhaps not agreeing with their decisions, so maybe the groupings don't look correct to you, but they seem to have made some effort to be "periodic".

[1] https://home.theodoregray.com/printed-products

I'm not criticizing you for this, obviously, but "heavier" is a silly attribute to increase as you go down the table. It makes sense for the actual periodic table, but here something like "complexity" "modernity" or "scale" would have made much more sense (to me, obviously).

But atoms literally get heavier as you go down the table. If the actual elements were ordered in complexity of compounds, hydrogen would be at the bottom of the table, and periodic table posters would have to come with a special “carbon” sticker to attach to the floor.

Yes, I'm agreeing that mass (or more accurately, proton count) makes sense for the elements. I'm saying it doesn't make sense for tools.

It feels like they were perhaps hindered by wanting to conform to the chemical periodic table format.