We have another new character making their debut soon in Injustice 2. The Atom will be taking his shrinking and growing skills to the fighting game and should be an interesting character to play out.
Ray Choi is this game's Atom as the original Atom, Ray Palmer, has gone missing. You can see in the video his many attacks in small form as well as one giant attack. The story goes he's trying to find the original Atom so hopefully, Injustice 2 will offer some answers in that area.
The Atom will be available soon as a DLC.