But I've been amazed at how many programmers don't like to have them. Why?
Even on normal keyboards I don't use it, and they are annoying because they make the mouse position awkwardly more to the right than it should be healthy for the arm (I really envy left handed people, they don't have to deal with this).
And it is next to impossible to get a keyboard without the numpad, fortunately I found two such keyboards and I have one at work and one at home (Logitech K310 and Microsoft Sculpt).
And I haven't seen in live any person that uses numpad, I always thought it is used by accountants only (and those that don't want to use two hands to enter numbers).
In short research, I found they are hundreds of them available on Amazon, Aliexpress. However, most of them have mechanical switches[0][1], some of them have conducted switches (like Topre[2]) and it is very rarely to see cheap, typical office-use TKL keyboards made by companies like Microsoft or Logitech but Matias have at least sell one model [3].
It might be handy to read a short guide [4] of keyboard naming by their sizes, whether you will look for new keyboard in future.
[0]: https://www.amazon.com/10-keyless-keyboard/s?k=10+keyless+ke...
[1]: https://www.keyboardco.com/category.asp?path=Mechanical%20Ke...
[2]: https://www.amazon.com/s?k=topre&ref=nb_sb_noss_1
[3]: https://www.keyboardco.com/category.asp?path=Mac/Standard/Te...
[4]: https://www.keyboardco.com/blog/index.php/2017/08/full-size-...