So, I had an idea for a future campaign where spells and magical abilities would be color coded based on the user's alignment. Good and Evil would be white and black respectively, while Lawful and Chaotic would be blue and red. Neutral on either scale would be a greyish silver color. For example, a Lawful Good paladin using their lay on hands ability would generate a blue and white aura and a Chaotic Evil warlock would have a black and red eldritch blast.
As far as magic items go, I was thinking of having their effects a Neutral grey but I like the idea of using the creator's alignment. I was also considering having hide/alter alignment spells be more common, and having items available that would have those effects.
Would this give too much information to the players? I want to run this in a 3.5 edition game. I plan for the PCs to deal with NPCs all across the alignment spectrum, even in ostensibly "good" organizations.
On a meta level the PCs would basically know the alignment of every NPC they saw using a magical ability, and I'm afraid that that knowledge could start influencing their actions in-game. There is also the issue that classes with no magical abilities like Fighter or Barbarian would not give their alignment away like that, which may be a potential handicap in their favor. I think it would be a nice little addition and would add some flavor to the magic system, but I also don't want to unbalance gameplay for it.