Sonic Tech: Through the use of sonic crystals, GDI is able to project a wave of sonic energy that can vibrate any target to piece. This is instrumental in abating the spread of Tiberium on Earth and while Tiberium isn't a threat to Earth anymore, with the Tiberium Control Network up and running; Sonic technology still has a place in GDIs arsenal. (Unlocks Shockwave/Shatterer, Sonic Grenades, Sonic Cannons)
Zone Armor: While it doesn't hold a candle to the stuff currently in use by the military, GDI does supply a variety of upgrade packages to make Colonial Militia Zone Troopers a combat effective fighting force. (Unlocks Basic Zone Trooper Armor, Zone Upgrade Packs, Zone Heavy Weapons, and Jump Jets)
Robotic Drone Tech: GDI have rarely used Robots in their arsenal, mainly due to the dangers of an enemy taking control of your own robots, the control signal being jammed due to interference, and study done decades ago that proves Humans supported by AI is superior than AI controlled armies. However, robots have found a niche for themselves as patrol and scout units. A recent robotic addition to GDI's arsenal is the War Dog which is a scaled down Mastadon frame with a machine gun head. Advanced sensors and pack intelligence makes it an ideal scouting unit while being very cheap to produce. (Unlocks War Dogs, Drone Swarm, Repair Drones, Custom Drones Designs)
Subterranean Tech: During the 2nd Tib War, GDI ruled the heavens but Nod ruled the underworld and they do that through subterranean technology. Nod used this network to great effect as it is the only place where they are protected from GDI Air superiority and our Ion Cannons. By the 3rd Tib War, Tiberium has grown deep within the Earth's crust and tunnelling through Tiberium is too difficult and dangerous, thus the tunnels were abandoned until the TCN has been established and managed to clear most of the Tiberium, allowing Nod's global tunnel network to return to service. This technology is relatively simple and GDI saw potential in having a Tunnel Network in their colonies in the event the Scrin achieved orbital supremacy. It should be made aware however that unscrupulous individuals may make use of these tunnels if they are not properly supervised. (Unlocks Subterranean APC, Drill Pod, and Tunnel Network System)