In a medium bowl, combine the oats, pumpkin puree, peanut butter, ground flaxseed, honey, pumpkin pie spice, vanilla extract, and salt.

Stir until the mixture is evenly combined and thick enough to hold together. If desired, fold in mini chocolate chips or chopped nuts.

Cover and chill the mixture for 15 to 20 minutes to make it easier to roll.

Using a tablespoon or small cookie scoop, roll the mixture into bite-sized balls with your hands.

Place the energy balls on a plate or lined tray and refrigerate for at least 30 minutes before serving.

Store leftovers in an airtight container in the refrigerator.