I have an overwhelming desire for more details on how the Svartálfar live.
There's the distinct possibility the race no longer functionally exists anymore, given the collapse of their last ship, so I doubt further movies will expand upon them. Some might have fallen through portals and thus escaped the destruction, but there can't be anymore than a handful left unless there were others who did not kill themselves at the battle against Bor.
All we saw beyond their war-making was Angrim becoming Kursed, healing Malekith, and their emergence from stasis. We only see loyalists to Malekith because no one else is left, so we can't tell if there even ever were any other factions previously.
What is their culture? What do they consider food? Do they even eat? We don't see enough of Svartalfheimr to be able to say what if anything actually lives there, and we can't tell if its habitable anymore. They are creatures from beyond the universe, it's not entirely possible to make assumptions of what their requirements are.
All we know on the movie canon history for them beyond the film is what Eccleston said about Malekith, to quote Wiki quoting other sources:
"There is a kind of tragic quality to his quest. Because he’s lost his wife, he’s lost his children. He’s lost everything. And he returns for revenge. And the agent for his revenge is the Aether. If he gets hold of that, he is omnipotent."[22] Eccleston continued, "What I thought about a great deal was revenge—there's huge amounts of revenge. One quote is: 'When you seek revenge, be sure to dig two graves.'
That's it. (Apologies, Malegrim shippers, I suppose this wrinkle needs to be accounted for if you decide it enters your headcanon.)
Tangent: I just found out from wiki that Adewale Akinnuoye-Agbaje actually was physically playing Kurse in the film, rather than just doing motion capture, which is bloody amazing. Also, if you would like to see where they filmed the Svartálfaheimr scenes, let me introduce you to the Skeiðarársandur:
[Source], [Source] and [Source]. It's a volcanic desert in southern Iceland prone to flooding because of the glacier on the volcano above it, making it one of the least decisive landscapes the world has ever seen. Follow those links, you'll see what one of the floods did to a bridge in the area.
I suppose I'm spoiled for canon information from Elder Scrolls' effusiveness and Dark Souls' ability to be mined for secrets, which simply can't be done in a two hour film, beyond the written word, such as the book in Asgard or perhaps the Svartálfar script seen at several points throughout the film. I only knew the book was going to be seen, so I didn't have time to capture pictures of any of that text to see if it resembles functional language, or even just a simple cipher like the runes effectively were. I suppose when the film is released, the possibility of finding out will be opened to us.
But still, some extra information would be nice.