From Andy's messageboards:
So, do we still need a golfbag of weapons? Certainly this doesn't include the aligned-properties of DR, but it might allay some fears about needing 30 weapons with you...
Cheers!
There are only 3 special materials supported by the core rules as far as DR goes. This is to prevent the system from simply being a "screw" to the players--this way, they can do a little research and know what to bring along, or even just make sure that the party has a range of options.
Silver: the classic. Hurts werewolves and weaker devils.
Cold iron: long overlooked in D&D, this has plenty of legendary backing. Hurts fey (and some feylike creatures, such as eladrin) and weaker demons.
Adamantine: hurts golems and stoneskinned PCs.
I don't think you'll see much, if anything, added to this list in core D&D products. If I were adding a new special weapon material to the game, I'd probably figure out a way to "link" it to one of those above (for instance, you could say that "baatorian green steel" is the equivalent of cold iron for DR purposes), rather than leaving it out of the system entirely or making up a whole new category.
Andy Collins
Senior Designer
Wizards of the Coast Roleplaying R&D
So, do we still need a golfbag of weapons? Certainly this doesn't include the aligned-properties of DR, but it might allay some fears about needing 30 weapons with you...
Cheers!