So, what kind of keystone could traditional mages even get?

A lot of people complain about mages not having a real keystone, and I don't disagree, but what keystone could we even add that complements traditional mages?

And I realize that comet works for certain mages, but it doesn't really have the impact other keystones do. A lot of mages take Aery for the extra poke, even though it's meant to be a utility keystone for enchanters.