Preheat oven to 350°F (175°C). Line a 12-cup muffin tin with liners or lightly grease.
In a large bowl, whisk together flour, oats, flaxseed, chia seeds, pumpkin seeds, sunflower seeds, baking soda, baking powder, salt, and cinnamon.
In a medium bowl, whisk eggs (or flax eggs), applesauce/banana, yogurt, oil, vanilla, and sugar/syrup until well combined.
Add grated zucchini/carrot and apple/pear to the wet mixture and stir.
Combine wet and dry ingredients until just mixed. Gently fold in berries if using.
Divide batter evenly among muffin cups (they’ll be quite full).
Bake 22–25 minutes, or until a toothpick inserted in the center comes out clean.
Cool in pan 5 minutes, then transfer to a wire rack to cool completely.