A is for Ancient Artifacts (and also alliteration, apparently)

"Any sufficiently advanced technology is indistinguishable from magic." - Arthur C. Clarke

The use of Ancient technology IMTU varies a bit from canon. The Ancients left behind many more sites and many more gadgets, and even after 300,000 years, much of it still works. Possession of an Ancient artifact is still mostly illegal within the Imperium, but exceptions are sometimes made. It is not unusually for a museum to display bits of non-working Ancient technology. Universities and the military are occasionally loaned artifacts for study. The majority of discovered artifacts are kept safely tucked away in Imperial warehouses and labs.
But still, magic is fun. You’ve got to let the players cut loose once in a while, or they’ll want to go back to playing D&D. With that in mind, I try to stick to a couple rules when bringing an Ancient device into a game:

• It can’t be so powerful it causes game imbalance.
• It can be powerful, but only for a limited time.
• If the artifacts power is mundane, they can keep it indefinitely. They will still be arrested if caught with it however. 
• The Imperium is not stupid. Imperial Intelligence has a branch specifically tasked with retrieving Ancient technology, which by legal definition is property of the Imperium. 
• If the artifact starts to be used as a crutch, it will mysteriously stop working, explode, etc. 
• Artifacts are for dramatic, cinematic, and/or humorous storytelling use. Discussions on how the device violates the laws of physics or loop holing are frowned upon.

Dark Disk

This is a small, silver colored disk about 3 inches in diameter and 1/2 inch thick. It has no markings or apparent power source. When the center of the disk is pressed it creates a sphere of near total darkness. Pressing the center of the disk a second time will create a sphere of total darkness. Light intensifying goggles will not work in total dark, and no one can see in or out of the completely dark sphere. All other sensors (Infrared, auditory, etc.) will work normally. The edge of the disk can be rotated to change the size of the sphere anywhere from 5 feet in diameter to 40 feet in diameter. The dark sphere passes through all matter, including walls, floors, and ceilings, so activating a large sphere, on a starship for instance, has the potential of affecting several decks. Pressing the center a third time deactivates the device. The device will apparently run indefinitely and there are no known negative effects of its use.

Chrono Grenade

This is a small, hand held sphere with an adjustable time delay and activation switch. Upon detonation the devices stops time inside a 20’ diameter sphere and subsequently becomes an impenetrable barrier. Anyone caught at the edge of the sphere at the time of detonation suffers 4d6 damage. The time sphere lasts for one minute (or four 15 second rounds), after which the artifact disappears. A user holding an activated device in an empty room would simple see the device disappear.

Plasma Gauntlet

This is a silvery metallic glove with a glowing circle in the palm and will conform to fit any human sized hand including Vargr and Aslan. Once activated it acts as a recoilless PGMP-14 with +1 to hit. It has no apparent power source, but after each shot, the user loses 1 point permanently from one of his physical attributes (determine randomly). It also hurts like hell to use. The gauntlet can be fired once per round, if anyone dared to do so. The user is at -2 to do anything requiring dexterity with that hand while the glove is worn.

Consciousness Transference Device

This artifact is about the size and shape of a standard flashlight. It will transfer the user’s consciousness into whatever the “lens” end is pressed against. If the target is another living creature, like a human or animal, the consciousness of the user and target are switched. If the target is non-organic, like a toaster or computer, the user’s body becomes catatonic. The user gets the general sensation of what it means to be the target and has basic audio and visual input. If the target is a computer or has a computerized component, the user can take over that device on a roll of INT or less. The effect lasts 1d6+1 minutes or until the device is turned off. The device can be used once per in-game week or once per gaming session. If physical contact cannot be made with the target, the device also has a beam mode. The beam range is 20’ and must stay in contact with the target for a continuous 15 seconds. If contact is not maintained the device fails and cannot be used again until allowed by the conditions above.

Interphase Device

This device is worn on the forearm, like a bracer. When activated, it causes the user, his clothing, equipment, and all touching him (up to three additional people) to become temporarily out of phase with their current physicality. This enables the user to pass though solid material (in any direction). Once activated, the device will operate for 30 seconds (2 rounds) after which it will deactivate and start to recharge. The device will work up to 3 times per day. Using the device puts a strain on the bodies of all who use it. Upon passing through the material, the PC will temporarily lose 1 point of END per 1 foot of material thickness (round up). The player should announce his intentions for use to the referee prior to use. The user should focus (even briefly) on what he wishes to accomplish, as the device somehow knows the PCs intentions. The user remains visible and can manipulate physical objects while phased. Artifact researchers have been baffled by the device as testing has shown that, depending on the user’s thoughts, they can either pull an item out of a sealed box or just pick up the box itself. The device is known to also cause some neurological damage. Users must roll INT or less on 2d6 after each use to avoid losing 1 point of INT permanently.

The Silencer

This is a small white sphere about 2” in diameter with an activation button. When pressed the device will mute all sound in a sphere 20’ in diameter. The effect lasts for 2 minutes or until the button is pressed again, after which the device disappears.

The Crappiest Box of Holding Ever

This artifact is about the size of a dorm fridge, with a similar sized door. The box contains a miniature pocket universe about 10’x10’x10’. The device is clearly damaged however. Strange lights and sounds emanate from its cracked surface and items placed in the box have a 10% chance of disappearing immediately and forever. Items only have a 20% chance per day of being recovered. The opening is big enough to allow passage of most humans, but doing so causes the person to feel an incredible mental assault along with the overwhelming desire to get out. People wearing a psionic shield and who roll INT or less on 2d6 can stay in the box while only feeling mildly uncomfortable, otherwise they feel will the need to get out. Unshielded individuals forced to stay in the box will permanently lose 1 point of INT each hour or portion of an hour, until INT reaches 0 and permanent insanity occurs.

That's if for this one. If you are looking for more Ancient artifact inspiration, check out Warehouse 23 by Steve Jackson games.