Just a simple plugin to make numpad keys do the same thing as regular number keys in tmux.
Tested on MacOS
prefix + Numpad 0
same asprefix + 0
Move to window0
prefix + Numpad 1
same asprefix + 1
Move to window1
prefix + Numpad 2
same asprefix + 2
Move to window2
prefix + Numpad 3
same asprefix + 3
Move to window3
prefix + Numpad 4
same asprefix + 4
Move to window4
prefix + Numpad 5
same asprefix + 5
Move to window5
prefix + Numpad 6
same asprefix + 6
Move to window6
prefix + Numpad 7
same asprefix + 7
Move to window7
prefix + Numpad 8
same asprefix + 8
Move to window8
prefix + Numpad 9
same asprefix + 9
Move to window9
Installation with Tmux Plugin Manager (recommended)
Add plugin to the list of TPM plugins in .tmux.conf:
set -g @plugin 'lsparlin/tmux-plugin-mac-numpad'
Hit prefix + I to fetch the plugin and source it.
You should now have numpad keys that can be used to switch windows in the same way as top-row numbers.