Take a look Elements of Magic: Mythic Earth, which has several magic traditions that give you access to the magic Skills used to cast spells.
There's so many different concepts out there:
Animism: Everything from the smallest stone to the largest ocean, from a soft breeze to a raging inferno, has a spirit. The spirits embody and represent the elements, as well as concepts and such. In order to "do magic", you have to convince those spirits to use their natural powers on your behalf.
The language of Magic: The universe was created with a word - or rather, a language. The Great Maker talked everyting into being, and the words he used got infused with that power along the way, so now speaking his words means changing the very fabric of reality. The only thing is: It was the Tongue of the Great Maker, not pidgin orc, and it's hard to find out what the words are, what they mean, and even harder to pronounce them properly. Magic users of this path try to learn the words with their proper pronounciation, exact meaning, context, so they can use them. If they pronounce something wrong, the magic might not work. Or the effect is quite different from what they hoped.
Conduit of Heaven and Hell: Power rests with Greater Beings of the Outer Spheres, and they grant it to those who further their goals and submit to their ideals.
The Weave: Magic is like a great net underlying all reality, and wizards learn to grasp the net ant twist it, altering reality to suit their wims.
Gems of Power: The universe was created with raw power, which transformed into stone and steel and earth and the wind and everything else. Some of the power remained in its raw form, though, and some substances seem to collect and accumulate this power, changing it in the process, "colouring" or "flavouring" it. Let's say that precious stones are those materials. So the crimson light of ruby speaks either of raw destruction or of unbridled passion, while sapphires with their soothing blue light will heal you - or freeze you to death.
Fortunately, these gems aren't prone to leaking, so you won't be victim to the terrible power just by touching or even being near a gem. But there are those who know how to coax the power out of the stones. Combine different stones in different ways for different effects. Light reflected first through ruby (emotion, passion) and then sapphire (cold) will calm emotions, for example. Spellcasters don't learn spells, they learn the proper combinations of gems to cast their spells.
A gem only stores so much power before it is depleted, but it will be recharged over time.
Levels of Reality: Our nice, predictable, solid world isn't as real as we tell ourselves. Above our mundane plane of existance there is a higher plane, where the mind truly triumphs over matter, and ideals and outlooks are more real than elements and physical properties. The awakened mage learns how to reach beyond his own reality and, for a short time, draw the Higher Place down upon our world. Since it is the higher reality, its rules will supersede ours for as long as the connection stands.
The Great Mythos: In the dephts of time and space (and beyond both), there are entities far older and crueler than anyone could ever imagine. They lie in hiding, sleeping, but occasionally they whisper their dark secrets into the ears and minds of unfortunate chosen ones. Those poor souls invariable go stark raving mad within weeks, but before their mind is forever lost, they write down what they have heard, for others to read. You can read those dark secrets and see behind the curtain of reality, alter it in ways that should not be possible, but the price is your very sanity.