Preheat waffle iron according to manufacturer instructions and lightly grease if needed.
In a large bowl, whisk together flour, sugar, baking powder, and salt.
In another bowl, whisk eggs, milk, melted butter, and vanilla extract until smooth.
Pour wet ingredients into dry ingredients and stir gently until just combined.
Fold blueberries carefully into the batter.
Pour batter into the preheated waffle iron.
Cook until waffles are golden brown and crispy.
Repeat with remaining batter.
Serve warm with maple syrup, butter, or desired toppings.