Position 1 rack in top third and 1 rack in bottom third of oven and preheat to 350 degrees. Lined rimmed baking sheets with parchment paper.
Combine flour, brown sugar, baking powder, baking soda, and coarse salt in processor; blend 5 seconds. Add butter. Using on/off turns, blend until mixture resembles coarse meal. Transfer mixture to a large bowl. Add one cup oats and blueberries; stir to blend evenly.
Stir half and half and vanilla in small bowl. Gradually add to flour mixture, tossing until dough just comes together (dough will be very moist).
Using 1/2 cup measuring cup for each scone, drop dough in mounds onto prepared baking sheets, spacing 3 inches apart. Sprinkle tops with remaining 3 tablespoons oats, then raw sugar.
Bake 15 minutes. Reverse sheets and continue baking until scones are golden and tester inserted from side comes out clean, about 12 minutes longer. Transfer scones to a rack and cool slightly. Serve warm or at room temperature.