Ok, this is my first post but I've been reading these forums for weeks. Time to contribute!
First off is a question, would you be able to have atium alloys of other alloys? Also as has already been stated an alloy is always a pushing metal so if you can double alloy (atium alloy of another alloy) would it then be pulling, pushing or some kind of double pushing :S
Anyway as for my list, I tried to apply temporal effects as much as possible as atium itself seems primarily temporal.
Iron: see future 'shadow' lines for nearby metals (where they will be) and can exert a time-delayed pull (pull on where they WILL be)
Steel: As Iron but with a push
Tin: Full sensory perception of the future, so hearing as well as just shadows alternatively more like a prophetic vision instead of a constantly moving image of the future around you.
Pewter: Not entirely sure, Mental fortitude maybe? or just making you smarter? (would be awesome to combine with a zincmind.)
Zinc: Portal to Shadesmar?
Brass: Portal from shadesmar? not sure what else would work for these 2 other than time delayed riot/soothe (kind of useful for a longer effect maybe?)
Copper: Create a coppercloud which is more like the time bubbles, only thing I could think of, so doesn't move basically or create a time-delayed coppercloud? Or possibly centre a coppercloud around someone else, protecting them from emotional allomancy.
Bronze: Detect future pulses.
Gold: Already known
Electrum: Maybe as normal atium but see only 1 persons future, or maybe see their ultimate future? -This is the one that made me think it may not work to create a double alloy
Bendalloy: Let everyone in your bubble see the future (group atium=Pure carnage, however also needs to be used tactically or enemies will also see atium shadows)
Cadmium: Let everyone in your bubble see the past (group malatium? more likely group gold, good distraction for people who aren't prepared)
(May have got Bendalloy and Cadmium the wrong way around, trying to think it through still)
Aluminum: Time delayed Aluminum? or I really like the permanent destruction of allomantic ability, anti-lerasium
Duralumin: Not sure, Understand a metals abilities better? instant-savant anyone? or I also like the permanent boost
Chromium: As with Aluminum but for others
Nicrosil: create savants?
That's all i can think of for now.