There's a recluse sect of warriors trained to be proficient with every weapon they come across with, and to use that capability to it's best, they're thought to harness and keep a pocket dimension for accessing all of their arsenal.

Arcane Arsenal

At 3rd level, you are able to create a pocket dimension specially prepared to store your equipment for a quick draw.

You can store equipment in the arsenal during a short or long rest, spending at least 10 minutes concentrating for each new equipment stored. You have to be touching the weapon during the ritual to do so. This counts as a light activity during a long rest. You can have a number of equipment stored equal to your Fighter level + your Proficiency Bonus.

Summon Equipment. When you make an attack on your turn, you can choose to summon any weapon stored in your Arcane Arsenal to an empty hand. After you make the attack, you can choose to keep the weapon in your hand or dispell it back to the arsenal as part of the same action.

You can summon only one weapon as part of your attack, but you can also spend an action or bonus action to summon an equipment or dispel it back to the arsenal.

When you reach 10th level, you can store and summon armor, summoning them directly on your body and replacing the one you had donned and sending it to the arsenal.

Summoning Reflexes

Also at 3rd level, when you make an opportunity attack, you can use a weapon stored in your arsenal to do so. You need at least one free hand to do it, and you can choose to keep the weapon after the attack.

You can use a reaction to summon a stored shield when you are hit by an attack, potentially turning it into a miss.

After 7th level, you can use a reaction to summon a stored shield when an ally is hit by an attack within 5ft of you.

Using the shield with this ability always returns the shield to the arsenal after the reaction.

War Dance

At 7th level, you can change weapons in quick succession, making consecutive attacks against your opponents. When you score a critical hit on an attack roll, you can make an additional attack with another weapon that is stored in your arsenal. You need at least one free hand to do so.

Improved Arsenal

At 10th level, you can store any equipment in your arsenal with an action. You can only store armor that is not being worn by another creature. You can store a weapon or shield held by another creature if you succeed in a Dexterity Check against the creature’s AC as an action.

Armored Whirlwind

At 15th level, you don’t need to have free hands to summon your weapons with your abilities, as they float around you. Also, when you miss an attack, you can use your bonus action to roll an attack with advantage with a weapon that is not in your hands.

Living Arsenal

At 18th level, you can summon your weapons with astonishing speed. Everytime you hit one of the attacks of your Attack Action, you can use your reaction to make an extra attack with a stored or summoned weapon. The weapons summoned in this way remain floating around you.

Also, with a bonus action, you can summon all of your stored weapons at once to assume a protective stance to shield you from damage. You receive resistance to slashing, piercing and bludgeoning damage, including from magic weapons, and enemies that hit you with a melee attack take 3d6 slashing damage.

This effect lasts for a number of rounds equal to your Intelligence modifier, and you have to Concentrate on the effect for the duration, as if concentrating on a spell.

You have two uses of this ability, and you regain all expended uses of it when you finish a long rest.