I've built myself a Redox (Open Source split keyboard).

That one has a number row. Also due to the possibility of programming multiple layers I can hold down a key on the left half, then use the right half as a numpad.

It would also be possible to program it as a toggle button to switch to jumped more, so you don't have to hold it down, but I prefer not having some kind of invisible state in my keyboard that I have to keep track of.