Entity Descriptions
From NS2 community wiki
Ambient Sound
Armory
Base Structure
Cinematic
Commander_camera
Command Station
Door
Doors presumably have open/close/break code attached to them.
hive
infantry portal
location
A location entity is used to give an area a name. When placed in the editor, it is a small gray square, you can scale this up to the size of the room you want to name. You can also use multiple location entities with the same name if your area for when your entity has an unusual shape.
It is also mandatory for the Power Grid. When a power_point is placed inside a location entity, it will use that area, all lights located inside them will be affected by the power_point's status. Unless the lights are set to Ignore power grid
masc
minimap extents
places a movable red cube. select to access the Edit window where settings can be changed.
particles
places a purple ball and stick object. Select it with the Select in order to get its Edit window where settings can be changed
Player_Start
Adds a marine shaped entity to your map. ?? Is this where you spawn in the ready room or during play??
power point
ready room start
resource point
places a resource point. These are where teams can collect resources to buy abilities, equipment or buildings.
reverb
bright green cube. It's edit window has a "Type" setting for different environments for sound to reverberate in.