Pulse oats in a food processor just until slightly ground. Transfer to a large bowl. Repeat with flax seeds, then almonds, and finally pumpkin seeds, pulsing just one ingredient at a time.
Add puffed rice, milk powder, cranberries, protein powder, sesame seeds, chia seeds, and shredded coconut to the bowl; mix to combine.
Mix almond butter, peanut butter, honey, coconut milk, vegetable oil, and vanilla together in a quart-sized bowl until well combined. Pour wet mixture into the dry mixture and stir until well blended. Spread thinly onto the prepared cookie sheet.
Place in the freezer until solid, about 1 hour.
Remove from the freezer, dust with oat bran, and cut into 24 bars. Store in a zip-top bag in the refrigerator.