The original Starcraft: Brood War expansion game had eleven units per race. With the exclusive info released by PCGamer (August 2007 edition), Blizzard Entertainment revealed at least 16 units should be expected per race.  Below you can take a look at the description of each Protoss Unit.

Zealot

Zealots are the standard infantry unit of the Protoss. Equipped with psionic blades for melee combat, zealots may confront zerglings and marines in battle with ease, unless outnumbered. In Starcraft II, Zealots have a new ability named Charge with which they can close in on enemy ranged units such as Terran Tanks.

Stalker

Stalkers are an enhanced type of dragoons operated by fallen dark templars. The Stalker may be used as an anti-air and anti-infantry unit. Stalkers also have the blink ability to teleport and close in on fleeing enemies.

Immortal

Immortals are effective against Terran tanks and heavy ranged units. Their enhanced shields will deflect most of the damage against enemy units with powerful ranged attacks. However, Immortals are vulnerable to light weapon units such as Terran Reapers and Zerglings.

Observer

Confirmed to return in Starcraft II, but details of enhancements or new abilities are not yet revealed

Colossus

Colossus are four-legged mechanical units equipped with two beam guns that sweep through enemy units one at a time., destroying marines and zerglings. They are effective assisting packs of Zealots. Keep them in the back and protect them. Colossus are vulnerable to Banelings and reapers. With their long legs, Colossus units can walk through obstacles and hills with ease.

Phoenix

The Phoenix are anti-air flying fighters with a fearsome ability. When the enemy brings in multiple air-units, the Phoenix can be used to destroy them by activating its overload ability. A net of beams successfuly wipes anything caught in its perimeter. A vulnerability to using this ability is that the Phoenix remains offline for some seconds not able to move or attack. Enemy units still in the area could take advantage of this weakness to destroy the Phoenix.

Phase Prism

Phase Prisms replace the Scout transporting vessel. They are used to warp-in up to sixteen protoss units anywhere on the battlefield. Phase Prisms also serve as a mobile pylon to power up protoss buildings when enemy units have destroyed pylons. Phase Prism is useful to build a quick defense at a new Nexus for expansion of your mineral and vespene gas resources. Phase Prisms could be used to power phase cannons strategically placed to surprise enemies in unsuspecting areas.

Warp Ray

Warp Rays are anti-air and anti-infantry units with additional damage the longer they fire a single target. Warp Rays can destroy Terran Battlecruisers and Heavy Zerg flyers more efficiently than Phoenix units. Warp Rays can be used to destroy enemy buildings within seconds. Warp Rays are vulnerable to swarms of marines and hydras.

Mothership

The Mothership is at the top of the Protoss tech tree. Only one Mothership can be built at a time. Among its abilities are the Time Bomb which distorts time around a radius, slowing down enemy missiles and projectiles in mid-air. After the field shuts off, all projectiles fall harmlessly to the ground. The planet cracker is a series of energy streams devastating anything it encounters on the ground including ground units and structures. The Mothership has a ultimate ability named Black Hole. It may be used against large amounts of anti-air enemy flyers such as Battlecruisers, and Mutalisks. The Black Hole sucks in all enemy units within its radius.

High Templar

The High Templar still creates Psionic Storms, but has gained a new ability similar to Arbiter’s Stasis Field. The High Templar can effectively neutralize enemy units temporarily, while your forces take advantage. The High Templar ability allows Protoss players to create blockades as a strategic bottleneck or barriers to stop advancing enemy units.

Dark Templar

The stealthed melee units from the original Brood War are back. Enemies without detection units will be vulnerable to these expert ground assassins. New abilities have not yet been revealed.

Twilight Archon

They are the Protoss tank unit wreaking havoc through enemy defenses. Blizzard is still tinkering new abilities for this powerhouse. For now they are as Archons from the original StarCraft.

Tempest

They replace the old Carriers, equipped with an enhanced shield that activates when its attacked by ground units and defense structures. Tempest is vulnerable against air attacks. They unleash disc fighters against enemies.

Soul Hunter

Soul Hunters are robotic units that hover above the ground. They are anti-infantry units that suck the souls of enemies. The more souls they consume, the more powerful they get. They fire a single beam at first, and as they consume more souls it powers up to three beams, increasing its damage output. Soul Hunters are effective against small enemy units. Thirteen Soul Hunters can destroy a Command Center within 10 seconds.

Reaver

The old robotic-slug Reaver unit is back. With the use of a Phase Prism, the reavers are devastating against enemy SCVs and Drones. Upgrade abilities are still unknown.

Phase Cannon

Phase Cannons can now phase and shift into an energy form, similar to Warcraft III wisps, and move around freely to another location where it can materialize again to unleash its energy blasts. A Pylon or Phase Prism must be within range to become functional. However, if the Pylon or Phase Prism is destroyed before the Phase Cannon materializes, they are lost.

Star Relic

The Star Relic is a dangerous unit. It can create a cloak field to make ground and air units invisible, and even structures. Star Relic has a fusion beam ability against a single unit. It slowly causes damage until the unit dies. However, the danger comes after … the enemy unit becomes a living bomb, exploding and damaging everything around its perimeter. The bigger the unit, the bigger the damage radius when it goes boom.