I was thinking of a new quest idea. It goes something like this.
I was thinking evil wizard or something caught a unicorn and imprisoned it while harnessing its magical abilities or something. Your mission is to free it. Unicorns were very chaotic and the symbol of independent freedom. So an imprisoned one, would be very troubling to it and all of your chaotic good types especially. They had the ability to do small dimension door type teleports. So maybe the wizard is harnessing that ability and some healing abilities or something from it. I imagined unlocking the magical barrier that imprisons the unicorn, and unicorn shaking itself off like a wet dog. But instead of water droplets it would shake off rainbow droplets. The unicorn horn would then glow rainbow colors when realised and about to use its magic and teleport itself away off in safe distance from everyone when saved. A message pops up with a message of gratitude in the form of telepathy from the unicorn thanking you for saving it.
I think they live in magical forests so a new area might have to be created as well.
If you made the evil wizard lawful evil (because the unicorn is chaotic good...), it would appeal to druids who want to restore balance in the world by setting it free as well.
By the way, a unicorn pet would be a great idea too.