In Borderlands 4 Class Mods are the Build Defining Items you can equip that fundamentally change how your given Class plays, ranging from allowing you to Over Cap Your Skills to Unlocking New Abilities to allow New Playstyles.
Harlowe has got 6 Legendary Class Mods that have Set Powers and allow New Playstyles to be unlocked, whilst coming with a range of Set Skills assigned to them.
Each of these Class Mods have a Specific Boss they are associated with so you can Target Farm the one you want by killing the associated boss repeatedly until it drops.
Note: It's worth nothing that the Affixes and Skills vary on these Class Mods so it may take a few attempts to get the Perfect Roll for your build.
