Only one new game in that list and all of them were triple-A. There are some great single player indie games.
Age of Decadence [http://store.steampowered.com/app/230070/]
Cities: Skylines [http://store.steampowered.com/app/255710/]
Divinity: Original Sin [http://store.steampowered.com/app/373420/]
Endless Legend [http://store.steampowered.com/app/289130/]
Legends of Eisenwald [http://store.steampowered.com/app/246760/]
Sunless Sea [http://store.steampowered.com/app/304650/]
UnderRail [http://store.steampowered.com/app/250520/] (different game to Undertale, but...)
Undertale [http://store.steampowered.com/app/391540/]
Satellite Reign [http://store.steampowered.com/app/268870/]
Ok, that's nine, but there are a lot more.
