While my actual webcomic is still heavily under construction, one thing that I feel like I have pretty down is my Magic System. Mine is sort of an expansion on the concept of the 4 elements. I add 4 more, and all 8 together serve as the primal forces that power and influence our universe, as well as provides an umbrella for which most, if not all different kinds of magics can be stuck under reliably.
There are 8 elements in my magic table, broken into 3 categories. Basic, Balance, and Arcane.
The basic elements are the cookie cutter Fire, Water, Earth, and Air that we've all come to know and love. These 4 elements are the basic building blocks of habitable worlds. They're more tangible things rather than more abstract concepts, you can feel the breeze, rain running down your face, the warmth of fire, the earth beneath your feet, etc. Their simple nature makes them easier to channel and most beginners in magic will use them, hence the name basic elements. They also need to coexist on some level in order for a world to be able to foster life.
Which brings us to the Balance Elements, Light, Life, and Shadow. The basic elements are needed for an environment to foster life, but like any ecologist can tell you, there needs to be balance in every ecosystem. The balance elements are more abstract than the basic ones, while nature magic falls under life and can be tangible, its existence is also more abstract as well. Light and shadow are both more abstract in their concepts as well, they are life and death, day and night, good and evil, etc. Light and Shadow are forces that are always fighting, but with neither supposed to win, they maintain balance over life. If Shadow were to dominate Light, all Life would decay and die under its oppressive and potent magics, yet if Light were to dominate shadow, Life would grow uninhibited, smothering everything in a primal tide. The Basic Elements create a base for Life to grow, the Balance elements are to ensure it does so ideally. Because of the more abstract nature of these elements' purpose, they're harder to learn.
The final category has one element all to itself, which is the Arcane, the final element being Arcane. All magic among all of the other elements is essentially manipulating energy with a certain twist that changes the way that the energy is used. Those who practice the arcane do not influence it to form elemental magics. Instead, Arcane arts are those of pure energy manipulation. This is the art of the unexplained, the crazy mage things that don't seem to be able to be applied to any other element. Things like teleportation, shape shifting, illusions, constructs, etc. are all arts that are among the practices of the arcane. The arcane arts are vast and tricky, involving manipulating the universe's energy in its purest form to dozens of different results. It is tricky to place it on a scale because of its diversity. Some of it is simple, while some of it is very complex.
That's just the philosophy behind it though, I suppose it doesn't quite explain how it's used.
I don't have super strict guidelines and ideas for it at the moment other than the fact that one has to have the potential to cast magic in order to actually learn to channel the various energies. Magic is mostly preformed with one's own power and knowledge of manipulating it rather than through specific words and named spells. Also, learning one kind of magic attunes a lot of creatures to that element, making it harder for them to learn to use other magics. Balance magic is notoriously difficult to be able to channel more than one element in its category. Most people who focus on a balance element tend to have knowledge of one balance element and one to two basic elements. Basic elements are notorious for lacking the same difficulty among them, and while not too many completely master them all, most mages are capable of casting all 4 in some capacity. Since arcane is pure energy, it doesn't effect other elements as much as the others.
For those who lack the ability to channel magic from their being, they can still use objects that have been imbued with magical influence. While I mentioned earlier that magic tends to be performed with the mage's own energy, spellbooks and other artifacts exist that have already had power imbued into them. This allows non magic beings to still channel magic with these objects acting as a source. Spell books tend to have words and named spells specifically for non magic users to be able to utilize them. Crystals are known to be excellent magic conductors. Their structure can hold vast amounts of power and even more potent things such as souls. They're a popular choice as a sort of reserve battery for mages or a vessel of use by those with no magical potential. Objects imbued with magic can even be used in advanced technology as a source of power or ammunition.