Displacement wizards are able to stow something and make it appear in another place at will, this is not just limited to matter however. Through practice, a displacement wizard can learn to displace energy, space, and eventually time itself. 

(I haven't put too much effort into the flavor descriptions of the subclass, just wanting to know if there is anything that stands out as exceptionally broken.)

Conjuration Savant

Beginning when you select this school at 2nd level, the gold and time you must spend to copy a Conjuration spell into your spellbook is halved.

Astral Holding

Beginning at 2nd level when you select this school, you may stow tiny objects as a bonus action. These objects are teleported into a pocket dimension. You may retrieve any item inside this pocket dimension as a bonus action.

Astral Holding (Part 2)

Beginning at 6th level, you may stow objects up to medium size. You may also stow empty space. If you stow empty space, you may pull yourself up to 5 ft. in any direction OR pull a creature up to 5 ft. towards you, provided it fails a STR save with a DC equal to your spell save. 

You can retrieve this space and push yourself up to 5 ft. in any direction OR push a creature up to 5 ft. away if it fails a str save equal to your spell save DC.

To push/pull a creature, they must be within 10 ft. of you when you use this ability.

Astral Holding (Part 3)

Beginning at 10th level you may stow objects up to large, as well as a number of medium or smaller creatures equal to your intelligence modifier (minimum of 1). To hold a creature, make a melee spell attack using your intelligence modifier, if the attack hits, the target is transported to your pocket dimension. Holding a creature requires concentration, if this concentration is broken, any creatures stowed get instantly teleported out of the dimension next to you.

Additionally, as a reaction, you may stow a single projectile or spell that targets you. This nullifies the damage of the attack. You can release said attack as part of the same reaction or hold it and release it as an action, with the attack roll modifier being your spell attack modifier, and the save being your spell save DC. You may use this feature a number of times equal to your proficiency bonus. You regain all expended uses on a long rest.

 

Astral Holding (Part 4)

Beginning at 14th level, you can stow objects and creatures up to large. You can also stow not just space and matter, but time as well. As an action, you may remove yourself and creatures of your choice within 5 ft. of you. When you remove the time, it skips your and the other creatures’ turns in combat, but you and these creatures cannot be targeted until the start of your next turn.

You may place this time as an action, you and any creatures that were with you when you removed the time get 1 sub round of combat (or 6 seconds of stopped time) (initiative stays the same). During that sub round, all creatures are effectively paralyzed (not paralyzed condition), and cannot see you move, hear you speak, or feel your touch or any other sensory effect you give off (if they are attacked they will feel the wound). 

You may use this feature once per long rest.