1. All the icons should have a background matching their type: square for spells, octagonal for abilities/evocations, and + shaped for invocations.
2. The various schools and gods have associated color schemes; Cheibriados invocations are teal, ice is blue, translocations are a certain shade of purple. Obviously it's fine to use colors from outside of these as necessary, but using the "right" color is encouraged.
3. Don't get hung up on trying to represent the spell's effect exactly. A strong, memorable symbol is far more effective as an icon than an exact diagram of what the spell does. For examples, see Sticky Flame and Lugonu's Banish invocation.
4. If the existing icon is fine, there's nothing wrong with simply modifying it to fit the new style and applying the correct background.
I've attached an image with the blank backgrounds and a few examples; there are dozens more already pushed to trunk.
spellicons.png [^] (6,812 bytes) 2014-06-03 04:45
6.20.spells.png [^] (8,122 bytes) 2014-06-21 00:01
firestorm.png [^] (2,172 bytes) 2014-08-15 01:26
