I see no use for the numlock key, I'd rather just have the numpad on the whole time. Are there actually cases where it is useful or people who for some reason prefer their numpad turned off?
Scroll Lock is the one that comes to mind as a safe removal.
However, for me, the real useless AND inconvenient piece of shit I wish I could rebind as I want that space for something better is Caps Lock. Unfortunately, it's not that easy to do.
Use autohotkey! I have a very simple solution for this, where the caps lock key is mapped either as a backspace key, or it minimizes the current window.
You should look into Kanata. It lets you remap the whole keyboard, same idea as QMK, except it's running on your computer instead of the keyboard itself.
It can be a bit tricky to set up if you're not used to that sort of thing, but I managed to figure it out so if you have any questions feel free to ask.