Earth/Air - Base unit of earth magic is gold, which appears according to some kind of noise algorithm which could theoretically be determined. It appears in various dense locations rather than evenly spread. It just sits there (of course!). The more gold there is, the more magically saturated the region becomes, and plants grow well, the water just tastes good, etc etc, and thus creatures migrate here.
Gold collects. Then, once it has been collected intentionally, air magic doodads appear spontaneously and densely around such "hoards". This makes the hoards focal points for living things. Thus, trophic levels are created, with Hoarders being at the top. Bit of ley line action between hoards. The gold is barely or not at all elementally weighted *other than earth*, but the air doodads are very elementally weighted (with air and otherwise). Monsters will go after livestock and attack cities (major hoards).
Gems are not as good a power source as gold, but they have a lot of elemental influence; when used as spell foci/etc, it will not be as useful as gold, however, it is HEAVILY weighted towards its element, and therefore is more efficient than gold WHEN used on a same-element spell.
Raw gems appear according to a different algorithm than gold. They are all heavily aligned to a specific element. Raw gems are lumpy (sort of) or other interesting shapes which generally are not jewelry (lumpy overlapping cubes). You can create a magical item by strapping a raw gem to an item. Metal magic is used to refine gems and infuse them with more of a specific effect.
Changing gem shape is fairly simple, so they tend to end up pretty.
Fire/Water - Tends to do area effects in wedges or arcs. (Expanding hollow vs fireball) Actually tillted (not 90* personal defensive or area offensive generally
Light/Dark - tends to do spherical effects that are either dispersed or very tightly focused (ie, light spell, or ray effects). Also, cylinders. personal offensive or area defensive generally
Rules for doodads - repelled by doodads of same alignment, attracted to doodads of opposite alignments. When doodads of opposite alignments meet, storms brew. Large concentrations of doodads are necessary to create storms perceivable by humans. Furthermore, there is an activation threshhold; doodads create storms only when affecting a physical object or creating a physical object. Carrying many magic items increases the activation energy needed to change you. Magic items attract same-alignment doodads and repel opposed-alignment doodads. They also create same-alignment doodads.
The universal game is like a large multiplayer game of smash up - each player desires to screw all other players, but not to be screwed. Also, anti-magic is like the baby trying to get up on the table and eat all of the cards - alll players are trying to stop said baby.
Null magic - stasis, freezing, cut off somebody from source of magic, presence of null = presence of nothing = vaccuum = spatial warping
World is old since no one's "won" - no one creature has become balanced and gained all the magic energy to become the new 7th element.
Antichaos - easier than chaos. Any generic antimagic spell utilizes this. The big 'evil' of the setting. Keeps itself going at the expense of everything else. Chaos only wins if idea unites world. Forms mindless creatures mirroring normal chaotic universe.
Astral Cord - tiny tiny bubble universe at the end. Can feed energy to it to have it act as a battery for energy. Nothing there naturally. Similar energized universes can meld together, form larger universe. City of Brass very large one in fire plane. Theoretically could wrap one around to steal energy from another, enthralling them. Most dead people's spirits go to their demiplane, leaving behind base instincts in corpse, if they have a belief shared by a signifigant nomber of other people in some thing.
Paraelementals - theoretically infinite number - stronger at specific fractions of alignment - simpler fractions make for stronger paraelementals 1/3, 1/2 both good. Paraelemental planes are smaller than true elemental planes, and sufficiently unusual paraelementals don't have a natural plane to live in.