Im asking this because i actually found a staff that increase Phys DMG done…
Is this some kind of trolling by IMC? or am i missing anything?
As far as i know Kinos Psychic Preassure and some other skill of his (Magnetic Preassure? Gravity Pole?) is Physical Attack. Maybe even some of Featherfoots skills could be physical (like Ngadhundi and Bone Pointing?).
Imc ? Trolling ? Noooooo 
Or maybe it works like Arde dagger - fire property attack - but in this case it adds some physical attack to spells used (instead of fire). Need confirmation.
No, they are magic attack (non-element type).
The only things that come to mind would be using a dagger or whacking with C while equipped with a staff…
Lethargy buffs Strike damage on the target by 100%.
Being frozen buffs strike damage by some amount I don’t know.
But its - as you just stated - a buff … it doesnt profit from increased phys dmg …
the C swing with a staff/ the C stab with a dagger are the only ways for wizard to deal physical damage