GDI Buldings (So far) :
Tiberium Refinery (Cost : 2000) : The sum total of your cash reserves come from the Tiberium crystals that grow on the earth's crust. All Tiberium harvested is delivered to the Tiberium refinery. Tiberium cannot be used to create other buildings or units until it has been transported and unloaded in the refinery. Once Tiberium is inside the Tiberium Refinery, it undergoes a short process extracting all the goods and minerals from Tiberium which can be exchanged for other buildings and units on the battle field.
Requires: Power Plant
GDI Vehicles (So far) :
Hover APC (Cost : 800) : As most forms of water where declared unsafe after the thorn infestation the old design and plans for a fast moving amphibious APC on wheels had to be scrapped. With the thorn infestation anything that touches them could get heavily damaged. The Hover APC was designed to move up to a total of 6 soldiers across the field safely protecting Infantry inside from outside fire and protecting itself from any ground / water hazards.
Requires: War Factory

Kazuar (Cost : 600) : The Kazuar was designed to keep civilian towns / cities safe. The Kazuar is equipped with a rapid Vulcan cannon, which is effective against both light vehicles and most infantry. It's quick mobility and decent amour makes up for the Kazuar's weapon, which is not Anti-Air, or effective against heavy units. With it's weapon leaving anything around it's target un-damaged after heavy fire, It's the perfect unit to have protecting an allies base, or guarding a specific structure from enemy assaults.
Primary: Rapid Vulcan Cannon
Requires: War Factory

Hum-Vee (Cost : 400) : The Hum-Vee is only seen being used by the GDI In areas which are known to have Ion Storms. The Hum-Vee is a downgraded version of the Hov-Vee unit which can not be used in Stormy areas as it uses the GDI Hover technology, The Hum-Vee is called out to take place of the Hov-Vee in stormy situations. The Hum-Vee is armed with a dual rocket turret capable of eliminating lightly armored units and aircraft.
Primary: Dual-Rockets
Requires: War Factory

Hover Tank (Cost : 650) : The Hover Tank is the GDI's basic assault unit. The Hover Tank is armed with a small anti-armor cannon and a small anti-infantry machine gun making it lethal to all forms of battle-field units apart from aircraft. Hover Tanks are capable of causing a very large amount of damage when in large groups but are not very effective in smaller groups.
Primary: Machine gun.
Secondary: Anti-Armor cannon.
Requires: War Factory.

Scatterpack (Cost : 700) : The Scatterpack is GDI's main anti-air unit. The Scatterpack is armed with many rapid Gatling cannons capable of ripping infantry and aircraft to shreds in a matter of seconds. Due-to the heavy Machinery, the Scatterpack isn't very fast but can easily defend itself against Infantry and aircraft and is also quite effective against heavy armor in large groups.
Primary: Anti-Infantry cannons.
Secondary: Anti-Aircraft cannons.
Requires: War Factory, Radar.
GDI Infantry (So far) :
Informer (Cost : NA) : This unit is a top infiltration unit, The informer is able to get in and out of any bases eliminating any infantry on guard with ease and destroying the buildings with C4 charges after infiltrating them. The Informer is also hired by the GDI to sneak into Nod bases and act as a spy, stealing top secret information and informing GDI operatives. The Informer is a very valuable unit but will not be of service to you in your missions one hundred percent of the time.
(This unit is not trainable in game)
Primary: Inaccurate Sniper
Secondary: C4
Requires: NA
This Unit Is Only Available In The Campaign!
Light Infantry (Cost : 100) : The Light Infantry is the GDI's basic soldier. These soldiers are capable of quickly moving across most forms of terrain and eliminating other lightly armored infantry. In large groups light infantry can be devastating to most forms of units, but in small groups they are very vulnerable. Light Infantry, like most other unprotected soldiers are harmed by Tiberium.
Primary: Mini gun
Requires: Barracks

Engineer (Cost : 500) : Engineers are trained to repair heavily damaged structures in a very short amount of time. Engineers are also trained to re-wire enemy structures to work for their faction.
Requires: Barracks
Primary: Repair Kit

Rocketeer (Cost : 600) : The GDI Rocketeers are trained to pick off enemy targets at high altitudes with their custom designed machine gun. If a Rocketeer is to come under attack by enemy anti-air defenses, they are trained to land and attack on foot.
Primary: Machine Gun.
Requires: Barracks, Radar.

Medic (Cost : 600) : Medics are one of the most valuable soldiers on the field. While unarmed, medics normally move with large forces of infantry as they are capable of healing any friendly soldier in a very short amount of time.
Primary: Medical Equipment.
Requires: Barracks.

Grenadier (Cost : 200) : The G.D.I. Grenadiers are armed with Discus shaped explosives which are designed to damage armored units. The ammunition of which the Grenadiers carry is highly explosive so these units rarely travel in large groups.
Requires: Barracks
Primary: Discus Grenade
GDI Aircraft (So far) :
Orca Fighter (Cost : 1000) : The Orca Fighter is the basic G.D.I. Aircraft capable of moving at high speeds and firing high speed heat seeking missiles onto enemy targets.
Primary: Red-Eye Missiles
Requires: Airport