The Last of Us Walkthrough: Tommy's Dam: 2 Artifacts, 2 Firefly Pendant, 1 Training Guidebook, 2 Comics
Artifact 1: Power Plant Map
Inside the power Plant, in the small cabin behind you, you will find the map of the power plant.
Artifact 2: Plant Schematics
The story leads you through the power plant. You will come across a large blueprint of the power plant lying on the table in the control cabin.
Firefly Pendant 1: Ryan Oliverio
After the clash, go to the back room where the turbine is located, you will find the Pendant in the closet.
Firefly Pendant 2: Brent Pino
After find the ranch house walk straight into the back room, you will find the pendent on the desk.
Training Guidebook 1: Smoke: Chemistry
During the tour of the Tommy’s dam you will come across two technicians. Besides the two you will find a training guidebook for your smoke bombs.
Comic 1: Foreign Element
At the beginning of the chapter you climb hill and to the right, at the corner.
Comic 2: Zero Point
On the upper floor, where Ellie is staying, you will find another.