zinc garnet
From testing items, the ones that DON'T count damage:
(quest log says it doesn't)
Summon rings
Blazing Shell
Spike Boots
Firewalker Boots
Electrostatic Treads
Only Items that do seem to work:
Shadow Cloak
Gogorn Mask
Unsure items that I didn't test:
Thunder Crown
This quest doesn't seem to be tested much....
lusty ridge
Only items that directly deal damage count, so you are correct in your listing with the exception of echoing band. This has been confirmed to work. Thunder crown should work, but doesn't, dont waste your time there. You forgot the uncommon defiant plate and thornfists too.