The last type of gear you can get access to in Borderlands 3 are Artifacts which grants some sort of useful attribute to the character that equips them. This includes augmenting parts of your Vault Hunters abilities and making your character invulnerable for a brief period of time if their health drops below 50%. Check out our Artifacts Guide to find out everything you need to know about them.
To unlock Artifacts in Borderlands 3 you will need to progress through the main story missions so that you reach Eden-6. Upon doing so you will unlock the Artifacts slot in your loadout and towards the end of the story mission on this planet you will need to defeat the monster that is protecting a vault that contains the Eridian Synchronizer which is the item you require that will grant you the ability to unlock and equip Artifacts.
Artifacts drop randomly from defeated enemies or loot boxes, they can also be given as rewards from quests and will sometimes appear for sale from Zed's vending machine. Although there is a huge variety of Artifacts in Borderlands 3 you need to ensure that the ones you equip will actually be useful for your character and the action skill they are using.
Check out our How to Unlock Weapon and Item Slots guide to find out how you cang get more weapons and gear.