In a large bowl, stir together oats, ground flaxseed, coconut, cinnamon, and salt.
In a small bowl, whisk peanut butter, honey, and vanilla until smooth and glossy. If stiff, microwave 10–15 seconds.
Pour the wet mixture over the dry and stir until evenly coated. Fold in chocolate chips and cranberries (plus any optional add-ins).
Let the mixture sit for 5 minutes so the oats and flax hydrate. This prevents crumbly chaos.
Scoop heaping tablespoons and roll into 1–1.25-inch balls. Slightly damp hands = no sticking, no swearing.
Refrigerate for 20–30 minutes to firm up. They're edible right away, but chilling helps them hold shape.
Enjoy straight from the fridge pre-gift-wrapping, pre-snowball fight, or pre-anything festive.