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human
[LoTR] What are the best canonical feats of magic used by Gandalf, Saruman and the other Istari/wizards? And other Middle Earth Magic questions

In both the movies and the books. I'm just trying to compile a list of observable feats of magic in the Tolkienverse, it's hard considering how vague Tolkien's own image of magic was at times.

When the wizards did see fit to use their power, what could they actually *do*?

For that matter, what magic was available for the elves to use? Why couldn't humans do such things, to any similar extent?
gpt
Gandalf (the Grey) was able to battle Durin's Bane for 10 continuous days, the first eight spent in falling to the bottom of a chasm that had never been measured, and climbing a staircase that led to the very peak of a mountain. The next two days were a constant battle between Maiar. Gandalf described what it would have looked like to outside observers (most likely *very* different from what it actually was) as 
> the mountain was crowned with storm. Thunder they heard, and lightning, they said, smote upon Celebdil, and leaped back broken into tongues of fire.

Now, that's fun and all, but not particularly concrete. We can however now scale Gandalf = Balrog which gives us much more solid evidence of power.  This particular Balrog was able to solo the entire dwarven kingdom of Moria. So 1 Balrog>Thousands of dwarves, although, most likely in small groups. That's not even beginning to cover all the ridiculous things other Balrogs have done in the past. The 3-7 of them, were able to drive off the demon spider-thing Ungoliant, with 
> a tempest of flame.  

This same spider had recently devoured the light of the trees of Valinor(the fruit of which later became the sun and moon of Middle Earth), and had swelled to such a size that Morgoth himself(Sauron's master), was actually terrified. This is all still Gandalf the Grey, mind you.

The next example comes from Gandalf's next (physical) appearance in the Two Towers. Aragorn, Gimli, and Legolas all attack him believing him to be Saruman, cause, ya know. He was wearing white. Gandalf responds, by ripping Gimli's axe from his hands, forcing Aragorn to drop his sword, by making it burst into flame, and as Legolas shoots at him, disintegrating the arrow mid-flight with fire.

The next viable showing come from his extremely brief clashes with the Ringwraiths. He was able to drive them back with 
> a shaft of white light.   

Going further into detail let's talk about the Witch-King of Angmar. His main weapon was fear, such immense fear that he was described as

> A great black shape against the fires beyond he loomed up, grown to a vast menace of despair. In rode the Lord of the Nazgul, under the archway no enemy had ever yet passed, and all fled before his face. All save one. 

That one being, obviously Gandalf. Now, this does demonstrate great courage, but who cares? It's just fear. But the Nazgul wield greater weapons (at least 1-v-1. Against an army fear is pretty effective). For example he shattered Frodo's sword from about thirty feet away, by *screeching* at him. Then we have something that is debatable as being his power, but I'll still use it. 

> Then the Black Captain rose in his stirrups and cried aloud in a dreadful voice, speaking in some forgotten tongue words of power and terror to rend both heart and stone. Thrice he cried. Thrice the great ram boomed. And suddenly upon the last stroke the Gate of Gondor broke. As if stricken by some blasting spell it burst asunder: there was a flash of searing lightning, and the doors tumbled in riven fragments to the ground.  

And Gandalf was fairly confident he could fight this thing, on even terms. Other things Gandalf can do: Read minds and memories, bless a particularly pudgy pony, so that it could safely make it back to the town of Bree, despite all the hungry goblins and trolls in the way, knock Wormtongue to the floor/unconscious, and generates fire on plenty of occasions.