Focusing on the study of dimensional magic these mages boast tremendous potential, even if most don't reach it. The Bag Mage earns its title from being able to store a vast collection of items in a pocket dimension, much like a bag of holding. Bag Mages are sought after by merchants and traders to easily transport goods. If you don't stop there and keep with the training, Dimensional magic can become quite potent, utilizing teleportation and dimensional phasing.

Inventory

You can access your own personal extradimensional inventory with just a word. While touching an object, as a bonus action you may speak the words "Inventory, add..." and then the object name, the item will be instantly added to your inventory, and appear to have just vanished. As a bonus action you may also say "Inventory, remove..." and then the object name, the item in your inventory will be removed and appear before you. As a bonus action you may make a spectral parchment appear with a list of all items in your inventory. The list can be organized in any manner, but will always show every item. As an action you may create an illusion of any item in your inventory, the illusion lasts for 1 minute. Your Inventory has a number of slots equal to 4 x your wizard level. Each inventory slot is a cube with its sides equal in feet to that of your wizard level (A 2nd level wizard will have 8 slots that are 2ft x 2ft x 2ft, a 9th level wizard will have 36 slots that are 9ft x 9ft x 9ft). Inventory slots may not hold living creatures or constructs. Sentient items and artifacts (and high level magic items at the DMs discretion) may make a WIS saving throw to resist being added to your inventory, if the item resists, it becomes immune to this ability for 24 hours.

Blink

At 6th-level, as a bonus action you may teleport yourself, a willing creature you can touch, or an item you can touch, up to 60 feet away to an unoccupied space that you can see. A sentient item or artifact may make a WIS saving throw to resist being teleported. You can use this feature a number of times equal to your Intelligence modifier (minimum of 1). You regain all expended uses when you finish a long rest.

Phase

Pushing the limits of Dimensional magic has revealed startling truths, one of these is that walls don't have to block your way if the builders didn't build with 4th, 5th, or even 6th dimensional beings in mind. Beginning at 10th-level, as an action you become a flickering projection of yourself as you exist in multiple dimensions at once. For 1 minute, you can pass through solid walls and floors. If this ability ends while you are in a wall or floor, you suffer 10d10 force damage and are violently shoved to the nearest open space. You can use this ability twice and regain all expended uses when you finish a long rest.

Mental Inventory

At 10th-level you have become so familiar with your Inventory that you can access all the functions of it without speaking command words. With just a thought you may add or remove items. You can also choose to only show certain items on your inventory list.

Phase dodge

Skilled Bag Mages have taken dimensional magic far enough that it can be used defensively in combat. At 14th-level, as a reaction you can cause an attack that would hit you or a creature within 60 feet of you to pass harmlessly through. When you use this feature more than once since your last long rest, you gain one level of exhaustion. Only by finishing a long rest can you remove a level of exhaustion gained in this way.