Dungeons & Robots is an interesting looking Early Access action RPG that looks very promising and the developers have confirmed it's coming to Linux soon.
It does have a few negative reviews about performance and stability, but since it's Early Access that's to be expected. I look forward to giving it a go at release.
The developer said this on the Steam forum:
QuoteWe are going to upload in the next 2 weeks a beta version for the Linux. We will make a post when the beta will be available :)
About the game (From Steam)
Dungeons & Robots is an Online Action Shooter RPG, where players team up to battle various enemies, collect resources and dominate territories. Features include, fast-paced combat; elaborate crafting and inventory system; customizable characters, weapons, armour, powers and skills; procedurally generated environments and items; solo missions, 1-4 player co-op, and guilds. Explore these futuristic dungeons to fight, conquer and dominate.