"assign different effects" is the problem I am having.

I see your point about Sponsored Magic. There are a number of benefits that go beyond the effects.

Outside the five elements in the book, how to you determine what other elements might cover?

I'm trying to put together one based on the seasons. I would think it would need to be less useful/powerful than Seelie/unseelie Summer/Winter, unless being able to tap a supernatural knowledge pool is worth that much more?

Spring - renewal, rain
Summer - heat, light, growth
Fall - wind, decay
Winter - cold, darkness, death

Or just rename the current ones with a more narrow purpose, so;

Spring - Water
Summer -Fire
Fall - Air
Winter - Earth

Thanks