There are certain Injustice 2 attacks that are so essential to fighting that they’re basically the same for all characters.
Crouching jab (down + light attack)
The crouching jab hits mid, but with the speed of a high jab. This is a great move to intercept an attacking opponent, and if it successfully counters, it opens up a big opportunity for your own attack.
Uppercut (down + medium attack)
Maybe you’re familiar with the classic Mortal Kombat uppercut, the most iconic move the series has short of Scorpion’s "Get Over Here!" This move is fairly quick and knocks your opponent into the air, allowing a small combo finish.
An uppercut is good as an anti-air counter and against players who mash out too many high attacks. However, the uppercut must be used judiciously. If your opponent blocks, they have a big opening to land a free hit themselves.
Sweep (down + heavy attack)
A fast, heavy low attack that knocks your opponent down, the sweep is a great way to stop your opponent’s advance and set them up for an attack of your own. It's not something to use up close, as you’ll be pretty open if you’re blocked.
Depending on the character, the sweep can also be a strong distance attack. If you’re at a good distance, it’ll be hard for your opponent to punish your sweep even though the recovery of the move is fairly long.
Heavy strike (back + heavy attack)
This is a very slow mid attack. If it connects, a heavy strike will either bounce your opponent off a wall for a big combo opportunity or knock them through the wall for huge damage and a change of location for the fight.
This has many uses and is a go-to move for combos, especially after moves that freeze or stun your opponent.
Overhead attack (forward + heavy attack)
This is the one overhead move that everybody has — a big, slow strike that bounces your opponent against the ground to start a combo.
Not all of these moves are made equal: Some are faster than others, and others have animations so subtle it’s hard to tell the character is winding up.