Please stick with what monsters should be able to do by the PHB / Monster Manual. Don't give basic goblins any potions, scrolls, superpunches or anything that simply isn't there nor should be there.
(Also don't give them "levels". Monsters don't have character levels, only Challenge Ratings.)
Nothing precludes a DM giving goblins potions in the game. To channel jeremy crawford "If the enemy creature was not able to hold additional items, the description would say so"
