In a large bowl, stir together oats, ground flaxseed, chia seeds, cinnamon, ginger, and salt until evenly combined.
In a small microwave-safe bowl, gently warm peanut butter and honey for 15–20 seconds to loosen. Stir in vanilla.
Pour the peanut butter mixture over the dry ingredients. Stir with a sturdy spoon until no dry pockets remain. If it feels crumbly, add milk 1 tablespoon at a time.
Fold in dried cranberries and chocolate chips. Press and smear with the spoon to distribute evenly—this is sticky, embrace it.
Cover and refrigerate for 15–20 minutes to firm up. This makes rolling faster and less messy, IMO.
Scoop tablespoon-size portions and roll into balls between your palms. Aim for 18–22 balls depending on size.
If using coatings, roll each ball in coconut, pistachios, or cocoa. Holiday sparkle, unlocked.
Place on a parchment-lined tray for 10 minutes to set, then move to a sealed container.