while a lot of ships were equipped with tractor beams there is a variance in power of said tractor beams(imperial star destroyers and executor class star destroyers were equipped with militarily grade Q7 tractor beam projector which were designed to work offensively, rather then just to help guide friendly ships into port), as well as the number of tractor beams the ship is equipped with. you also have to take into account that the beams pulled not only the ship the projector was grasping but also the ship the projector was attached to, trying to pull a dreadnought heavy cruiser or an imperial star destroyer with a tractor beam mounted on a Nebulon-b frigate would likely lead to the Nebulon-b frigate being pulled instead. while a nebula class star destroyer would be better it is still only a third of the size of an imperial class star destroyer and I don't believe it is fitted with milatary grade tractor projectors(or at least ones which equal a Q7 tractor beam projector.