up coming titles i know off, fable, deux ex, ashes, i also heard rumors at some point that some released games might patch for DX12 compatibility, like the witcher 3 and Arma3, but haven't heard anything since for almost a year now.
i wonder if the new tomb raider will be DX12, since that is the API used for xbox.
Don't forget Gears of War UE, expected before March 2016 I believe

Could end up being Microsofts flagship DX12 game too I would think.