Quest Reward (Unfarmable)
In Borderlands 3 Quest Rewards are rewarded during or after a quest.
This Quest Reward isn't farmable, because it's a DLC Quest Reward or 1 of the rare outliers.
So after the quest is completed there is no easy way to farm this Quest Reward.
The only way you can farm this Quest Reward is Read-Only farming and some are also available in the Diamond Loot Room.