Bongos actually. You have to modify it to setup more action bars though.

I used to use Flexbar - SO MUCH HARDER TO USE.

Go under actionbars, set it to the number you need. 12 for the Xkeys Pro single layer, 24 for alt,ctrl, shift modifiers.

Then set them up individually and assign keybinds and if you did 24, then hide the other 12. Make sure you set the modifier for each action bar - right click it and set alt to 1 for example to have action bar 1 become 2 or 12 for action bar 1 to become 13.

Unhide to drag new macros/etc to the second layer.

What used to take me 5 hours takes 10 minutes. SO much better.