In approximate order by increasing absurdity:
pewter
We've already seen a pewter savant, right? I'm pretty sure Vin was one.
gold
electrum
Don't forget cerrobend and cadmium! Of course, the potential for going completely insane is a lot less for pulsers and sliders than augurs and oracles, but people who do everything more and more slowly (as dependency on the metal increases) or quickly would be nuts.
duralumin
chromium
nicrosil
aluminum (moved to be with its group)
Those would be interesting, especially if the user is just a misting.
atium
ULTIMATE COSMIC POWER. Itty-bitty living space.
lerasium
See atium's entry, except they'd develop a dependence on constantly gaining power to burn metals more effectively. If you had anyone mainline lerasium for any amount of time at all, they'd be able to launch themselves out of the atmosphere using the core of the earth.... I'll take an order of infinite lerasium and atium, please.
malatium
And we hit a snag. Brandon said that there are 16 (or 17, he didn't actually say a number) types of malatium, depending on what you alloy atium with. The malatium in the book is made using gold, and Vin sees TLR performing actions from the past. We know what electrum malatiumatium would do (basically atium, but with a larger time gap, and only one possibility shown) if it works the same way as gold malatium, but beyond that, I'm drawing a blank. If your event is before mine, let me know which questions you didn't get to and I'll ask him those.
The most interesting question derived from the metals I can think of is this: What does lerasium malatium do? (Not to mention malatium lerasium. Mistings that can only burn specific kinds of malatium, here we come!) Does the atium just enhance the effects of the lerasium? Of course, I'm kinda confused about how all of the atium alloys but gold and electrum work. If we can get just one more revealed, it will be much easier to crack the code. Lerasium turns someone into a mistborn, so would lerasium malatium make a super-mistborn? Are they even compatible as alloys, or would they destroy each other on contact?