I'm fairly confident I've found the undershirt worn under the Fjallraven shirt. Unfortunately its NOT the Todd Snyder sweatshirt and the thing that tipped me off was actually from the latest ep of Ted Lasso in Amsterdam. He's wearing an orange Todd Snyder x Champion sweatshirt, and the v-stitch at the collar is too big to match the undershirt in the Last of Us. Also, in the scene wearing Joel is digging Henry's grave, you can see the hem style, and its not that longer "sweatshirt" type hem, it matches to this shirt.
Its from National Athletic Goods, their Gym tee in Oatmeal. Made in Canada and can't buy direct from them but stocked at a decent amount of stores. Pretty sure its oatmeal, but lighting could make it look that colour when its actually the ash grey
These images below really sealed it for me; right click and click "open image in new tab" to see higher res version.
National Athletic Goods Gym Tee in Oatmeal is a light-to-medium weight Japanese mock twist jersey long-sleeve tee with a speckled mélange throughout. These long-sleeve tees are a popular cut from NAG due to their accommodating body and fabric that allows you to move easily.
www.witheredfig.com
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