Daeron Targaryen, son of Prince Maekar, had dreams that came true (THK: 513)
There are hedge wizards who claim to be able to foretell how the seasons will come (II: 189)
A three-eyed crow might be a magical representation of a person skilled in magic of some sort (II: 320-321)
A magician may find it easiest to contact a person with magical potential when they are near death (II: 320)
The "third eye" is a metaphor for the ability to use magic in some way. When it is "open" a person can see beyond the normal: whether a person's heart is good or bad, the acorn an ancient tree grew from and the stump it will one day become, or gaze south to the Summer Sea and north beyond the Wall (II: 321)
The third eye might be closed, but in sleep it may sometimes flutter open, as it does to allow a warg to have wolf dreams (II: 383)
Storm's End is ancient, its stones woven with spells so that no magic can pass. The spells are forgotten, but still In place (II: 455)
There is an example of two wargs speaking in dreams to each other, despite being removed by hundreds of leagues. It's possible that this happens only because one of them appears to be even more than a warg (yet both of them have the "three eyes") (II: 560)
An strange old dwarf woman exhibits prophetic dreams (III: 249, 250, 491)
A magic horn reputedly able to summon krakens from the deep (III: 408, 603)
There are women said to be woods witches among the wildlings, and sometimes their sons and daughters are said to have gifts for foretelling the weather (III: 466)
The old gods are said to still linger at High Heart, keeping a red priest from looking into his flames and seeing visions (III: 492)
A cloud of ravens descends upon a group of wights, seemingly commanded by a man (III: 536. V: 61-62)
There is a hidden gate as old as the Wall at the Nightfort, called the Black Gate, which only a man of the Night's Watch who has said his vows can open. It is set deep in a wall of the well at the center of the kitchens and is made of white weirwood with a face on it. A glow seems to come from the wood, like milk and moonlight, but very faintly. The face is old and pale, wrinkled and shrunken, its mouth and eyes closed and its cheeks sunken, its brow withered, and its chin sagging. (III: 635, 638)
The Wall is more than just ice and stone. There are old spells woven into it, strong enough to keep creatures of a magical nature from passing it (III: 636)
When someone approaches the Black Gate, the eyes open. They are white and blind, and then door asks, "Who are you?" A man of the Night Watch must repeat a part of his vows. The door will open then, saying, "Then pass", and its lips will open wider and wider still until nothing remained but a great gaping mouth in a ring of wrinkles (III: 638)
Water on the upper lip of the gate is strangely warm and salty as a tear (III: 638)
The Horn of Winter is huge and black, eight feet along its curve and so wide at the mouth that a man's arm could fit to the elbow. It is banded with old dark gold, more brown than yellow, and graven with runes (III: 836)
The Horned Lord once said that sorcery is a sword without a hilt. There is no safe way to grasp it (III: 836)
Its said woods witches are harmless, knowing no magic but perhaps having knowledge of little herb-craft and some midwifery (IV: 544)
A man who does not eat, sleep, breath, or drink, but who is afraid of fire. He reveals he is dead, brought to life by magic. His inability to cross the Wall is due to the magic in the Wall itself preventing it (V: 63, 69-70)