With the recent addition of the revisited artificer class to 5e, I did a quick playthrough with a level 3 artillerist. The artillerist can summon a turret; an object (not a construct) with a speed of 15 and they can command the turret to move as part of a bonus action. When I attempted to move the turret out of melee range of an enemy NPC, the DM tried to make an attack of opportunity against it. I pointed out to him that opportunity attacks are made against creatures, and the turret is not a creature.
This got me thinking about whether or not you can make opportunity attacks against other objects that move, such as a vehicle or even a rolling stone.