Xenonauts is a sci-fi themed turn based strategy game that plays in an isometric view.
Shadowrun: Hong Kong is a steam punk sci-fi themed turn based strategy RPG.
X-COM: UFO Defense is the original X-Com game that was released in 1993. A turn based battle game with resource management mechanics.
Call of Cthulhu: The Wasted Land is a turn-based strategy RPG set in a world of Lovecraftian horror.