In a large bowl, stir together oats, rice cereal, ground flaxseed, cinnamon, and salt.
Gently heat the almond butter and honey/maple syrup in a saucepan or microwave until smooth and pourable. Stir in the vanilla extract.
Pour the warm mixture over the dry ingredients. Mix until everything is evenly coated. Fold in chocolate chips or dried fruit once cooled slightly.
Refrigerate the mixture for 15–20 minutes to firm up.
Use your hands or a small scoop to roll into 1-inch balls. Press tightly to help them stick together.
Refrigerate in an airtight container for up to 1 week or freeze for 2 months.