Some confirmed upcoming Linux releases (a few of them thanks to Unity4 adding support for Linux) include:
Shadowrun Returns , Double Fine Adventure (led by Tim Shafer), Faster than Light , The Banner Saga , Nekro , Rival Threads: Last Class Heroes , Z , Hexit , Carmageddon: Reincarnation, Wasteland 2 , Legends of Aethereus and lastly from the creators of the Spacequest series Space Venture !
Others are on the verge of offering linux support. The potentials include Takedown (offering a Linux based on demand), Starlight Inception , Legends of Eisenwald , and Defense Grid 2.
Other current titles with Linux support (many of which are already on the Steam store) can be seen in the listing of past Humble Bundles .