Almost a decade ago, Blizzard announced Starcraft Ghost, a stealth action game set in the Starcraft universe where you played Nova. As a Ghost unit, players would see Starcraft’s marines, siege tanks, and zergling from an on the ground perspective. Nihilistic Software was hired to develop the game and it appears they planned on adding new units to Starcraft Ghost too.
One of the game’s artists shared concept art for a Shadow Husk, which looks similar to a Templar. There’s also a Ghost-like Stealth Spectre and a Brain Spectre, a Zerg unit that sort of looks like Krang.
You can see all of the artwork, including neat-o sketches for Dark Templars, Zerg buildings, and Nova here. (Flip to the end to view it!)