Reportedly, all shards, if they happened to be on Scadrial, would be blind to metal. Since this would imply that (as has been stated by others on this forum) the various planets in the Cosmere have various focuses that affect the interaction of a Shard with that planet, I conclude the following:
I postulate that all shards, if they happened to be on Scadrial, would have the potential to take a physical aspect in the form of a "god-metal". The effect of burning a god-metal (based upon the two we know of) is to increase the spiritual connection of the burner to the shard whose metal it is, with some interesting side effects.
My question is this... If a given shard we know of was on Scadrial, what effects would burning its god-metal produce?
Known Shards- metal-effect
Preservation- Lerasium- increased ability to use Allomancy, grants mistborn status.
Ruin- Atium- increased ability to ruin effectively, limited ability to see and interact with future
Speculative:
Devotion- Aonaium?- increased power/efficiency of aons drawn, grants Elantrian status
Dominion- Skaium?-?
Honor- Tanavastium?- increased Surgebinding efficiency, possibly grant all Surges
Odium- Rayseum?- increased Voidbinding efficiency, grant all anti-surges (whatever they happen to be)
Cultivation- Anyone know cultivation's shardholder?- Increased ability to farm?
Endowment- Austreum?- Increased heightening from what ever Breaths you hold?
And now we get to the really fun speculation, what happens if you create alloys of the god-metals with each other?
Atium+Austreum-Increased heightening, and rip the Breath out of anyone around you?
Tanavastium+Rayseum-Universe Implodes?
Austreum and Cultivationum should create some really nice effects, the Shardic Intents seem to match up well.
Theorize! (I'll put anything interesting up here)