Preheat the oven to 325°F. Line a baking sheet with parchment paper or a silicone baking mat and set aside. Beat butter in a large mixing bowl until creamy. Beat in brown sugar and granulated sugar. Add the egg and vanilla and mix until well combined. In a large bowl, combine flour, oats, baking soda, salt, and cinnamon. Add the flour and oats mixture to the butter mixture and stir until combined. Stir in pistachios and fold in blueberries. Scoop out with a large cookie dough scoop. Bake for 12 to 14 minutes or until the cookies are light golden brown on top. Let the cookies rest for 10 minutes on the baking sheet before removing to a wire cooling rack to cool. Store cookies in an airtight container for up to 4 days.