Baublethief

Similar to a thief, the Baublethief specializes in obtaining and using magical items, trinkets and or artifacts. They tend to not be as physically capable as your cut and dry street thief, but they can utilize the items they find to have much greater potential.

Illegal attunement

Starting at 3rd level, you have the ability to attune to 4 magic items as opposed to 3. This number increases to 5 at level 13.

Eye for Value

When you choose this archetype at 3rd level, you gain the senses to perceive high quality goods. When you roll to investigate or to perceive magic items, trinkets, artifacts or items of high monetary value, you may add your dexterity modifier to the roll as well. Once per short or long rest you may use your action to hone your senses onto one item you can see. For one hour you have advantage on all Dexterity checks made to obtain that item. 

Use Magic Device

By 9th level, you have learned enough about the workings of magic that you can improvise the use of items even when they are not intended for you. You ignore all class, race, and level requirements on the use of magic items.

Mana Cloak

Beginning at 13th level, you can manipulate the focus of your magic items and trinkets. As an action you can destroy the magic properties of one item you have on you to immediately become invisible. This invisibility lasts for one minute or until you interact with an item you are not wearing or another creature. While invisible this way, your next attack will have sneak attack applied.

Thief’s Mark

When you reach 17th level, you have a unique skill that allows you to swiftly obtain and use items you find. Once per long rest you may mark a creature you see. Attacks against that creature that have sneak attack deal an extra 1d6. When the marked creature is slain you magically teleport any magic items, artifacts, trinkets or items of value onto your person in a place it can fit, or next to you. If any of the items require attunement, you may immediately attune to one of those items when teleported to you. When a creature that is marked dies you may use your bonus action to mark another creature you can see. This ability requires concentration.