Spell Thief

You steal spells and use magic items to fuel your abilities.

Cantrips

Starting at 3rd level, you learn two wizard cantrips of your choice.  You can cast them with your Cunning Action trait.

Arcane Initiate

When you choose this archetype at 3rd level, you learn a few basic spells that wizards normally use; you know two 1st-level spells from the wizard spell list.  You can cast each of them a number of times equal to your Intelligence modifier and regain the ability to do so when you finish a long rest.  Intelligence is your spellcasting ability for these spells.

Absorb Magic

Starting at 9th level, you can absorb magic from spells.  When a creature within 5 feet of you casts a spell of 5th level or lower, you can use your reaction to cast counterspell, as a 5th level spell.  If the spell succeeds, your next Sneak Attack deals [roll]3d6[/roll] extra force damage on a hit, but only targeting the creature you used counterspell on.  Once you use this feature, you can't do so again until you finish a short or long rest. 

Magic Item Expert

By 13th 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 and can attune to extra magic items. You ignore all class, race, and level requirements on the use of magic items, and can attune to up to 4 magic items at a time.

Charge or Drain Magic Item

When you reach 17th level, you can charge or drain a magic item. As an action, you can force a creature to make a Dexterity saving throw (DC 8 + your Intelligence modifier + your proficiency bonus), which it can willingly fail.  On a failure, you can restore charges to a magic item equal to your Intelligence modifier, or vice versa.  You can do so a number of times equal to your Intelligence modifier, and regain the ability to do so when you finish a long rest.