Ok, so the glyphs are all from the Boiling Isles: you could say that they're all gifted to people who know how to find them, but for everyone else who has the ability, they just make the magic happen. But the main glyphs are basically Ice, Light, Fire and Plants. To create other things, you have to learn how to combine the glyphs the right way. Water has to be combined with the main glyphs to be made.

It can happen, just not, you know, as easily as you'd think.