Bonus action to dash isn't super abuse able, considering all rogues get it at level 2. The strongest use of it is if you had a druid who could drop spikes on the ground so every 5ft translate into 1d4 damage.
The only limitations is you have to end your move closer to an enemy you can see. So you could grapple and drag a guy thru the spikes, as long as you ended up 1 square closer after the move. (technically you could use your movement first, dragging away, then use bonus to move back towards)
If you were an Orc Druid 3 (with pirate background for athletics) you could longstrider yourself for 10 movement, then spike growth, since dragging uses 2x movement, you would end up with 40 total movement using your movement and bonus action, or 8d4 damage from dragging thru spikes, you would still have your regular action you could dash with as well for an additional 4d4. You would likely eventually want maybe a level of rogue for expertise, or some levels in barbarian for fast movement/rage.
OR you can longstrider yourself then turn into a dire wolf, having a total of 60 movement speed, since aggression doesn't specify a body part that disappears you still have access in wildshape form. As long as the DM allows you to grapple (with your mouth) you could move 180ft/round using bonus and regular actions to dash or 18d4.
EDIT: Fixed typo.
