Noble Phantasm

Noble Phantasms (宝具) are "crystallized mysteries", armaments made using the imagination of humans as their core, and weapons or abilities owned by heroic spirits. They are the embodiment of the ultimate mysteries of a hero that symbolizes his existence through historical facts and anecdotes. They can be general weapons, such as sword, lances, or bows, support items, such as rings and crowns, or they can be abstract concepts, such as abilities and curses. Considered to be their trump cards, they are activated by channeling prana into them and releasing their true names, and this can only be done by their true owners. Noble Phantasms far outrank other non-legendary items, meaning that a C ranked Noble Phantasm is the equivalent of an A or A+ ranked normal attack. They are generally based off of previous incarnations of weapons, and with each cycle of transmigration a weapon undergoes, it becomes weaker. If faced with their predecessors, newer incarnations will generally lose during a confrontation. The current number of existing Noble Phantasms is very small, but they still exist in the material world. The only use of a Noble Phantasm in the modern age is Fragarach owned by Bazett Fraga McRemitz. The reason it can be used by a normal human is the members of her bloodline are "Tradition Carriers", who have the ability to reenact the powers of old due to the blessings of their god. Avalon, recovered by the von Einzbern family, also still exists as a Noble Phantasm.

It is possible to sacrifice a Noble Phantasm for an attack that is one rank higher, which is called a Broken Phantasm (壊れた幻想). If a Noble Phantasm is packed with prana, it can be made to explode after striking its target. However, as it is nearly impossible to repair a destroyed Noble Phantasm, and as they are the trump cards of Heroic Spirits, they are unlikely to take such measures.

Angra Mainyu
All the World's Evil A curse that that had put all of the evils of the world on one person; the person that became Angra Mainyu. Not a very useful one. The result is that even when losing the shell of a class, the normally directionless/alignmentless Prana of a Servant soul still has an alignment directed towards killing people. The alignment of Angra Mainyu itself could be said to be his Noble Phantasm. Normally not a problem at all, but given the way how the Heaven's Feel works.... Incarnation of it in the 4th and the 5th wars is as an enormous curse on all things in the world. Materializes as black mud initially (which will move on to the shape of a giant human in the latter stages) that dissolves and absorbs the flesh and soul of whoever gets in contact with it. If the person somehow doesn't get dissolved, then he'll go mad or have to deal with its after effects. A person with an extremely strong ego can avoid it. Heroic Spirits (or probably because the fact that they are heroes) will be affected by it as well in the form of receiving cursed flesh. Personally, if Angra Mainyu was actually born, I think it would have been like an End of Evangellion ending with an evil Ayanami Rei instead.

Avesta
The Universal Revelation of Inscribed Creation

A support-type Noble Phantasm that records events accurately but is incapable of doing any damage. It was probably used to summon Avenger in Heaven's Feel 3. By having his name removed from Avesta, the records of the person that had become Angra Mainyu were erased and he consequently became free from "order".

Hazanken
A weapon in Chinese legends. Can only be swung, but said to be able to even slice through mountains.

Helmet of Invisibility
A unnamed helmet that grants the wearer invisibility. It was given to Perseus to aid him in his quest to slay Medusa.

Kibisis
An anti-sealing Noble Phantasm. Used to reverse the Breaker Gorgon barrier.

Mirror Shield
An unnamed bronze mirror-like shield that projects information from the surrounding environment on its surface so the user can rely on that information to move around without having to move himself away from the mirror. It can also be used as a sort of detection device as it transmits the heartbeats of those in the area. Used by Perseus.

Sha Nagba Imuru
The all-knowing, all-powerful star

Ko-gil's Noble Phantasm. In the hollow ataraxia card game though. Does it really exist? Does older Gilgamesh even have it? Actually the name of Gilgamesh's legend (translated as: He Who Knows Everything).

A lot of people seem to be under the impression that Gilgamesh is a dope, but he's very knowledgeable and cunning, even as an adult; able to see through exactly what Shirou was trying to do prior to activating UBW (as to the number of traced weapons he was preparing; has fair enough knowledge of thaumaturgy), etc. Hence, this (card game) Noble Phantasm for taking a look at some of the cards in the opponent's hand and the stack....which is pretty useless actually, but hey.

Talaria
Winged sandals capable of flight. They were given to Perseus to aid him in his quest to slay Medusa.