They can assign the damage however they choose
its primary contribution to aggressive decks is disruption
Edric, Spymaster of Trest One of the best card-draw commanders in Magic, Edric, Spymaster of Trest offers a very good incentive to attack more often
Nikya of the Old Ways Another deck that encourages you to specialize, Nikya of the Old Ways just wants you playing creatures, so it should be fairly straightforward to pilot
Prison commanders accomplish this either by increasing your opponent's spell casting cost or taxing them for playing some sort of ability or interacting in certain ways
During your opponent's next turn, if this Pokemon is damaged by an attack (even if this Pokemon is Knocked Out), put damage counters on the Attacking Pokemon equal to the damage done to this Pokemon