Another source of Aether (Spoilers?)

[Ilenya]

I figured it was consumed and destroyed in the process.

See, that's my thought, but considering it survived Louisiox's usage, it could still be out there somewhere.

Edit, also had totally forgotten about Ysayle's usage of the Crystal of Light. It's probably nowhere as strong as the three I mentioned, but it does mean that there very well could be such an item.