I thought it might be both fun and useful to create a list of Items of Power that players might recover or seek throughout the course of their adventures:

Cuspis Sanctimonia

Initially appearing as a wand of gold or brass approximately a foot in length and topped with the symbol of the holy aquila, when a hidden button is depressed in the shaft the "bottom" end telescopes to a length of four additional feet. The tip of the staff is particularly keen and if used as a weapon behaves in all respects as a Force Spear. (1d10+5E, 6Pen, Damage considered Holy)

The primary effect of the Spear, however, is the Sanctifying of earth and repelling of demons. Should the wielder of the spear (who must be a faithful follower of the Emperor - may he forever hold the galaxy upon his shoulders, may his gaze never waver.) thrust the base into the ground (considering it is a Force weapon it may stick into most materials) and spend an entire round in prayer he may sanctify the ground around himself in a radius of 3 meters per point of WP bonus. Any demon entering this purified zone suffers 1d5 critical Energy damage -treated as holy - each round he remains in the area. The whorshipper may maintain this aura for one round per point of WP bonus, whereafter he must make a Willpower check with a cumulative -10 modifier; once this check fails the boundry of sanctity falls and the wielder is left weakened and unable to move (treat as if stunned) for 1d5 rounds.

Outside of combat the wielder may santify unhallowed grounds, removing from them the taint of warp or chaos. This process requires the whorshipper set the spear, as above, and pray before it. For each 3 minutes of prayer a 10 meter radius of surrounding earth is purified, to a maximum of 10 meters per point of WP bonus. Such ritual is often used to reconsecrate holy chapels or tombs so they might be used again without fear.

That's a really cool item, do you have any more by chance?

I'll have to work on that, I was hoping other people would have some suggestions as well.

Seele Nachte

Utilized by the brave Witch Hunters of the Ordo Hereticus for millenia, the Seele Nachte vanished from common knowledge some three centuries ago and has yet to reemerge in form or rumor; there can be no doubt, however, that should it appear once more the Inquisition would be highly vested in seeing it returned to its rightful owners.

Three foot of haft crowned with a double bitted axe blade forged of an unknown silver metal, the weapon is tremendously head heavy and requires two hands to wield with any effect. When it was lost the axe was adorned in purity seals and charms meant to protect against the ministrations of the heretical witch and sorcerer cults which count themselves among the enemies of mankind; today, however, it is likely the seals and charms have rotted away leaving a weapon which, upon initial inspection, appears quite plain. Closer examination, however, reveals holy prayers etched along the handle and an image of the holy aquila spreading its wings across the width of the blade - none of which appear to be part of the axe's original design, causing some to speculate that it was not originally forged with the cause of the Emperor - eyes of fire, heart of gold, mighty hands, raging soul - in mind. The Witch Hunter, however, would remind us that whyever and by whomever it was forged, it has since been consecrated to that end and sent many thousands of heretic psykers to their graves.

Do to its tremendous weight, the axe is weilded as a Great Weapon (2d10R, Pen 2) though the unknown metal it is crafted from holds an almost supernatural edge, giving it the Mono quality. The weapon's value to the Witch Hunter, however, reveals itself in its uncanny ability to turn aside psykic attacks directed at the wielder ... indeed so long as he wears it in plain sight or holds it the bearer of the Seele Nachte resists assults from psykers as if he were an untouchable. (this effect only protects the wielder) This alone would make the weapon tremendously valuable, however the weapon's hatred does not stop there, for once it successfully delivers the killing blow upon a psyker, the relic's final power emerges. Upon slaying a psyker, a kind of "karmic resonance" begins to pulse inside the metal, charging it - though the charge lasts only an hour and if not used in that time, disipates violently, causing 2 points of Fatigue to the bearer. During that time, however, should the axe's wielder become the target of an offensive psykic ability he may choose to forgoe the relic's dampening quality and instead attempt to deflect the attack back upon the psyker. In order to do this each person (the psyker and the wielder) must make an opposed Willpower test; (the axe wielder does so with a +20 modifier) should the psyker succeed the power effects the target as normal, though should the axe wielder succeed the full effect of the power is reflected back upon the caster as if he were the original target of the ability. The axe may only hold one such charge at a time and killing the psyker with a reflected power does not recharge this effect.

The relic is not without its dangers, however, for the people who forged the weapon possessed a fanatical hatred of psykers and once the wielder utilizes the weapon's special power (the "reflect") that hatred begins to pass onto him. While this doesn't mean the individual will begin killing his psykic companions in their sleep, it does mean that he will feel a natural distrust toward their kind and be prone to avoiding them whenever possible. Additionally, the axe man may not simply lay down this weapon whenever he wants the psyker to heal his wounds ... indeed, putting down the weapon within sight of a psyker requires a Willpower test at -30. More so, even should the bearer succeed the psykic deadness (untouchable effect) will continue to cling to him for 1d5 hours.

Scythe of Mellonius

A weapon of great potent, the Scythe of Mellonius was believed lost upon the Dauntless-class cruiser Repentance in M38, it was recently rumoured to be found upon the hulk Emulous as reported by Geth, Acolyte to Witch Hunter Ticonius. It is a short shaft, 1,3 foot long, in sparkling ebony. It looks somewhat like a human femur, polished and inscribed with holy runes. Upon chanting the holy words of power and pressing the hidden, depressed button one can empower it with the holy energy of the Emperor (he who protects, always vigilant) effectively activates the weapon. It then elongates and a blade extends at the top. No-one knows how long it actually extends to, but reports say it is between three and four feet. Wielded by one of the Imperium's greatest heroes, Mellonius was known for the Exterminatus of the planet Treubeth III and defeating the daemon prince Azzaroth of Khorne. It was known to turn evil, twisted, debased and vile human beings into what they once was again; fearful true believers of the Emperor. It often concluded in them committing righteous suicide in the name of the Imperial Creed. It is also said that it encites fear in the spirit of daemons, small and great.

The Scythe of Mellonius counts as a Great Weapon (2D10 Pen 2) with the Mono quality, as well as having the attribute Holy. If wielded by a powerful psyker it can activate the new psychic power Repent.

Repent

Threshold: 28.
Focus time: Full action.
Sustain: No.
Range: 10x willpower bonus metres the greater agents of the Ruinous Powers.
20x willpower bonus for the minions of the Ruinous Powers.


Effects:
Repent uses the holy femur of Ylwa the Pious, incorporated into the weapon (the shaft, before being activated) effectively pushing Chaos out of its host, or otherwise damaging its agents.
A Hard (-20) willpower test is made for the minions of the Ruinous Powers, inside the range of 10x willpower bonus metres in a circle from the caster, without the Daemonic- or From Beyond-trait to induce fear into their hearts and making them realize their faults and flaws and effectively making them need to repent and become one with the Emperor through holy suicide. It forces the minions (using the rule below) to aim their weapons at themselves, effectively pulling the trigger and taking their own lives while chanting the Litany of Repentment. If you not use that rule, it forces them, if they fail, to aim their weapon and fire one (1) round into their own flesh, dealing the weapons' damage ignoring the effects of armour and toughness bonus.

If you have read the Basic Minion Rules in the Tattered Fates, this weapon and this effect is meant for them. If you have not, I will explain it shortly;
Basically, it makes every 'unimportant' NPC or antagonist (those without names, harhar) have 1 wound making them go insane from 1 insanity point and become entirely corrupted and vile by 1 corruption point. This enables combat to be more fast-paced and interesting if you want to have large battles that are not meant to kill your PCs.

A difficult (-10) willpower test is made to daemons within 10x willpwoer bonus metres, damaging their corporeal form with a blasting howl of psychic energy (2D10+1 Holy damage). This effect, however has a heavy toll to pay and the power backlashes harshly to the caster - every time this power is used the caster takes 1d2 levels of fatigue. Though if he succeeds on a difficult (-10) willpower test, this effect is negated as the holy power of the Emperor courses through his veins, enabling him to further battle the enemies of the Imperium.

Ticonius said:

I of course meant 20x willpower bonus.