Resourceful Feat

You've mastered every play that'll give you an edge when it comes to using common items, and gain the following benefits:

Prerequisite: None

• You are proficient with improvised weapons.
• You can add your proficiency bonus to the saving throw DC against for common items used by you.
• When taking time to recover reusable items such as ball bearings or caltrops, no roll is required.
• Additionally, whenever you deal damage with alchemical acid, alchemical fire, caltrops, holy water, or oil, that damage increases by 1d4 at 5th level, and again at 11th and 17th levels.

Source: KCCC, page 125