Suggestions for the best boons for Witch Staff?

Hephestus's occasional 200 damage boon is one i really prefer.
Both for normals and specials although speicals have the 400 damage i believe.
 
Hephestus, Zeus and Hammer are my go tos if available. And yes, Chaos too if I have enough health. The buffs granted by chaos go along way in any given run.WOuld recommend getting those early as possible.
The ones i listed here may not necessarily work for you but these are the ones i think work the most with Witch staff. Happy runs.

and yes, these are some of the combos you can check out if you want to experiment more https://gamerant.com/hades-2-best-boon-combos-witchs-staff-abilities/