Global Defence Initiative - Infantry units  
Here is the complete list of GDI infantry units in Tiberian sun with descriptions and pictures:  
Picture   Description
  Basic infantry unit. I build 10 to 15 in the beggining of the game. They build very fast and are usefull for scouting the map and basic base defence. most effective when used in combination with disc throwers.
  Great unit for base defence. Effective against lighter vehicles and infartry. Be carefull because they can explode if they are in large groups.
  Engineers can capture enemy buildings and repair yours. They can also repair bridges. Best used in combination with ghost stalker.
  This is a commando. Put him and 4 engineers in an APC, then use the carryall and sneak them in your enemies base. There you will cause a lot of damage.
  Used to heal your damaged infantry units.
  Infanrty that can fly. They are poorly armored and are killed easily but cost quite a lot. I use them only when I have a lot of money to spare.