StarCraft II: Heart of the Swarm/New Terran units

Hellbat
Hellions can transform into tougher, slower and stronger walkers with shorter range but the splash damage is wider.

Widow mine
Widow mines attached themselves to enemy units and causes major damage in a radius.

Siege tank
Does not need upgrade to switch to siege mode and tank mode.

Thor
Can now switch between two modes, Explosive payload and the Punisher cannons.

Medivacs
Can now use a speed boost to get to places faster.

Removed units
The Shredder is now removed from the game.