Engineers being able to extract motes (now crystallized stuff) is underrated - people don't realize how much extra cash you make. If you combine it with Mining you can double your collecting. I guess that's not really related to boxing, more solo use.

The saronite bomb is nice, its instant cast AOE damage (lower level bombs had a cast time). Only problem with it is targeting the ground, but its not that hard. Just think of having 5 of those bombs go off during the course of a fight.