Helm: Commoner's Headband

Armour: Commoner's Garb

Gauntlet: X

Leggings: Commoner's Shoes

Where To Find: 

(Click the link above to view the equipment and watch the getting video.)

The helmet can be discovered on a corpse in Mt. Gelmir.

Other pieces are obtained as drops from Commoner enemies found in Stormveil Castle, Leyndell, Royal Capital, and various other areas throughout the game.