What do you mean, there isn't enough space to keep all the loot? If there's one thing the universe has an abundance of, it's space. All we've got to do is bring a little bit more of it over here.

Dimensionists use some form of trickery to break the physical laws of the universe. This gives them several options for expanding their inventory, but also a a few for folding space at a scale large enough to encompass themselves or others.

Dimensionist Fold and distort space.
caret-right Extraways Treat cover as concealment.
caret-right Hammerspace Pull things out quickly.
caret-right Null Zone Remove an area from reality.
caret-right Sanctuary Create hidden, safe rooms.
caret-right Skidbladnir Turn large objects into inventory items.

Dimensionist

Utility plus-circleBag of Holding: In addition to the standard light and heavy inventory lists, you have a third type: extradimensional. Your extradimensional inventory has five slots and can be used to carry whatever you want just like your light and heavy inventories do.

plus-circleSecrets: Only those with levels in Dimensionist can open an extradimensional inventory. While anybody can recognize that you're carrying more than meets the eye, nobody will be able to frisk you for what you've got in your third inventory.

minus-circleHard to Open: Accessing your extradimensional inventory requires a procedure of work and 1 point of Supplies. Once you've accessed it, you can freely add or remove items from it but the inventory will automatically close again at the end of the current exploration turn. Accessing it again in the future requires another procedure and point of Supplies.

minus-circleTake It With You: If you die or whatever while you have stuff stashed in your extradimensional inventory, it is unretrieveable. Only another Dimensionist can ever get such stored items back.

Extraways

Offense plus-circleThe Other Sideways: You cause your attacks and other ability effects to briefly pass through the fourth dimension before rejoining the third. Practically speaking, this means that they appear to pass right through solid barriers. You treat partial cover (failure chance 6) as partial concealment (failure chance 3) instead, and total cover (most attack forms impossible) as total concealment (failure chance 6) instead.

Hammerspace

Utility plus-circleMallet Time: You can remove items from your extradimensional inventory as a single action instead of using a full procedure.

plus-circleNo Withdrawal Fees: Removing an item from your extradimensional inventory does not cost any Supplies.

minus-circleSlow Deposits: Putting things into your extradimensional inventory still costs Supplies and a procedure. Hammerspace just removes the hassle and expense of taking things out again.

Null Zone

Utility plus-circleCleft of Dimension: As an action, you can temporarily pinch off a chunk of reality and send it elsewhere. A space of your choice within 5 meters of your position and all other spaces within 2 meters of the target space simply cease to exist. This does not create a hole in reality or anything like that- everything simply gets pulled together around the space that isn't there anymore. The Null Zone persists until the end of the current exploration turn, whereupon everything returns to normal.

plus-circleWhat That Means: In practical terms, this means that nobody can enter or access any of the selected spaces. Spaces adjacent to the Null Zone (in other words, the ring of hexes 3 meters distant from the chosen target point) are all considered adjacent to each other. Creatures can move from one to any other, completely skipping the null zone in between. Attacks and effects pass directly over the null zone without counting it against their maximum range.

minus-circleHarmless: Any creatures inside the Null Zone can choose whether or not they want to be shunted into another dimension along with it. (Helpless or unconscious creatures are automatically removed along with the Null Zone). Creatures that stay are moved to any free space adjacent to the Null Zone of their choice. Creatures that don't are removed along with the Null Zone and cannot take actions or do anything while nulled; to them it seems like no time has passed at all.

minus-circleSupplies: Roll a trigger die when creating a null zone; if the result is 1-3 then doing so costs 1 Supplies. You cannot create null zones if you have no Supplies remaining.

Sanctuary

Utility plus-circleInterior Space: You can unfold space to create an extradimensional room. You and anyone with you can enter your extradimensional space from the location you created it. The extradimensional space itself takes the form of a room matching the architectural style/surroundings/furnishings of the location in which it was created. Extradimensional spaces are exactly one hex large- enough room for a single human to stand in, but no more.

plus-circleDungeoneer's Respite: If you create a sanctuary while delving a dungeon, it gets added as a new node to the map attached only to the node in which it was created. When an exploration turn begins inside of a Sanctuary node, no exploration die roll is needed.

plus-circleSecret Garden: The entrance to an extradimensional Sanctuary space is hidden such that it will go unnoticed to casual observation. Anybody making a concentrated search or who already knows it's there can find it, but even then only a creature with levels in Dimensionist can actually open or close it and thus access the space it hides.

minus-circleLimited Persistence: An extradimensional space created via Sanctuary lasts until the end of the game session. Anything left inside it after the game ends is harmlessly ejected. You can also choose to end the effect early if you want. Nothing that was created as part of the space (such as furniture) can be removed from it by any means; it simply disappears if you try.

minus-circleSupplies: Creating an extradimensional sanctuary space costs 1 Supplies use.
caret-right Alternative plus-circleFull Room: You can create a larger room big enough for a small party to rest in (up to approximately 5 meters in any dimension) instead of the tiny closet you would normally create.

minus-circleHigher Cost: Creating a full-sized room costs 2 Supplies instead of only one.
caret-right Alternative plus-circleBender's Closet: You can create a very spacious room (up to approximately 50 meters in any dimension) instead of the tiny closet you would normally create.

minus-circleExtreme Cost: Creating a huge room costs 3 Supplies instead of only one.

Skidbladnir

Utility plus-circlePym Particles: You can reduce very large objects (such as artillery, vehicles or buildings) down to a very small size and weight, allowing you to carry them around as an inventory item. You can later spend an action to restore your carried object to its full normal size and function.

minus-circleCost of Folding: Reducing an object's size to make it inventory-carryable requires a procedure of work and one or more Supplies depending on its initial size:
- Objects up to human-sized (size category 1-5) cost 1 Supplies to reduce.
- Objects up to car-sized (size category 6-7) cost 2 Supplies to reduce.
- Objects up to house-sized (size category 8-9) cost 3 Supplies to reduce.
- Objects up to ship-sized (size category 10-11) cost 4 Supplies to reduce.
- Objects up to castle-sized (size category 12-13) cost 5 Supplies to reduce.

minus-circleFreestanding Only: If something is firmly attached to anything else, you can't reduce it with Skidbladnir unless/until you detach it somehow. Most buildings are very firmly attached to the ground.

minus-circleSuspended Animation: You can only reduce a living thing with Skidbladnir if it is willing or helpless. Living things inside of a larger structure when it is reduced that do not wish to be reduced along with it are ejected harmlessly. Any living creature that does get reduced by Skidbladnir does not eat, sleep, age or have awareness of anything while reduced.

minus-circleRoom To Grow: You can only return a reduced object to its true size if there is enough clear space available for the object to occupy.