Preheat the oven to 350°F. Grease a muffin pan, either 12-cup regular or 24-cup mini. For both sizes, 6 regular cups and 12 mini cups.
Pulse the oats or brown rice in the blender or food processor until it has a flour consistency.
Place the flour and baking soda in a bowl and stir or whisk to combine.
Add the eggs, applesauce, banana, and coconut oil.
Stir to combine the dry and wet ingredients well.
Place the batter into the greased muffin pan filling each one halfway.
Press 3 to 4 blueberries into the batter for regular-sized muffins or 2 blueberries into the mini muffins.
Add another layer of batter on top of the blueberries.
Press more blueberries into the top of the batter.
Bake regular-sized muffins for 20 to 25 minutes and mini-sized muffins for 15 to 20 minutes.
Remove the muffins from the pan and cool them to room temperature.