grab bag
(bag as gift that comprises mystery prizes) A gift, purchase, etc. whose contents are concealed until after a selection is made; a bag as gift that comprises mystery prizes.
(bag from which a gift may be withdrawn) A bag from which a gift or prize may be withdrawn (grabbed) unseen.
(hodgepodge) (figurative) Any random assortment, selection or possibility.
(food package of size suitable for sharing) A moderately large bag of crisps or other snack, suitable for sharing.
(bug-out bag) A bag containing essential items, which can be easily picked up and taken in an emergency.