Heat the oven to 375°F and line a 12-cup muffin pan with paper liners (or grease the cups).
In a large bowl, whisk the flour, oats, baking powder, baking soda, cinnamon, and salt.
In a medium bowl, whisk the eggs, Greek yogurt, honey, melted coconut oil, and vanilla until smooth.
Pour the wet mixture into the dry ingredients and stir with a spatula until just combined; the batter will be thick, so stop as soon as the last streaks of flour disappear.
Gently fold in the blueberries. If they are frozen, do not thaw them — fold them in quickly with the last few strokes.
Divide the batter among the 12 cups, filling each about three-quarters full.
Bake for 18 to 22 minutes, until the tops are golden and a toothpick inserted in the center comes out with a few moist crumbs. Cool in the pan for 5 minutes, then move the muffins to a wire rack.
Store cooled muffins in a covered container at room temperature for up to 2 days, or freeze them for up to 3 months.