Far Cry 5 features a range of collectibles – Baseball Cards are one of them. They are required to complete the Grand Slam Side Quest. Finding one of them is also required to unlock the Pack Rat Trophy / Achievement. Baseball Cards are only found in the northern region, Whitetail Mountains, mostly in smaller cabins.
There are 9 Baseball Cards in FC5.
Card #1 – F.A.N.G. Center Store
Card #2 – Cooper Cabin
Card #3 – northwest of Wolf’s Den
Card #4 – Widow’s Creek
Card #5 – western mountainside
Card #6 – Cedar Lake
Card #7 – Lansdowne Airstrip
Card #8 – northwest of Baron Lumber Mill
Card #9 -northeast of Baron Lumber Mill
For all other FC5 Collectibles check out these guides: