The Steam Database (SteamDB) was updated with a bunch of unconfirmed and unannounced games that had been hidden on Steam. A majority of the games that were revealed were platform games that were previous inaccessible on Steam, but there was one heavy hitter hidden amongst those games – Half-Life 3.
While Half-Life 3 has yet to be confirmed, Arc System Works has confirmed five games that will release in 2016 on Steam — one of which was included in the SteamDB update. The game in question is Guilty Gear Xrd -Sign-, it was confirmed for a Steam release today after being included in the SteamDB list yesterday.
This confirmation helps support that the other games listed are, in fact, real. Of course, we won't know until they are confirmed by the developers and publishers, but it's enough to get the hypetrain rolling.
Arc System Works also revealed the following games for a Summer 2016 release on Steam: Melty Blood Actress Again Current Code, Under Night In-Birth Exe:Late, River City Super Sports Challenge ~All-Star Special~ and BlazBlue Chrono Phantasma Extend.