StarCraft II: Legacy of the Void/New Terran units

Liberator
Anti air flyer that can turn into an anti-ground defense turret. Mostly effective against large numbers of smaller enemy air units such as Mutalisks, Phoenixes and vikings but not big air units like battlecruisers, corruptors or void rays and carriers.

Cyclone
New ground unit that can lock onto enemy targets and move while firing. Effective against slow expensive targets like Thors, Ultralisks, Immortals etc. but vulnerable to fast moving targets like Mutalisks and zerglings.

HERC
Campaign unit that is immune to acidic explosions.

Battlecruiser
Can now teleport anywhere even to places that are not revealed to the player. Also in the newest patch they don't need energy to use any abilities including its teleporting and Yamato Cannon abilities.

Viking
Its ground attack does bonus damage to mechanical.

Raven
Its auto turret feature does more damage.

Siege tank
Used to be carryable in siege mode but not anymore.

Thor
Its splash damage to enemy air affects a wider area and it can switch to doing bonus damage to armored flyers.

Banshee
Can be upgraded to fly faster.