1-5, Q, E, R, T, F, G, H, Z, X, C, V
All of those with a Shift + variant.
A few of them with with an Alt + variant (only the ones that are comfortable and rarely used)
3 special buttons on the side of the mouse. All three bound with a shift, ctrl, and alt variant totalling 12 binds.

The further the keys reach from WASD out of ideal comfort range, are binds that are used less commonly for example, "T" is a bit more of a reach than "E". So T would is a less common ability used.

This gives me about 50 battle keybinds. Which I have found to be perfectly adequate to bind everything I need in battle, including potions, pet movements, focus target, etc.
I may have a few others I am forgetting about right now becuase im not at home but I think thats everything!

Whichever way you choose just make sure your hands are comfortable. Its awkward at first but your hands will get use to it all.