Team Fortress 2 Classic - List of Entities
base.fgd
tf2c_base.fgd
tf2c.fgd
Unimplemented FGD entities
Entities defined in the FGD that aren't implemented by the engine. These won't work when placed in Hammer unless they're internal.
Undocumented map entities
Entities used in the official BSP map files that are undefined in the official FGD. These will most likely work in-game, but require custom FGD code for Hammer.
Dynamically spawned entities
Entities that are created by the game code dynamically as needed. Spawning them manually or placing them in maps may lead to strange behavior, such as no model being applied.
Leftover entities
Various entities that the game engine claims to support but are leftovers from other source games. Some use assets that aren't included, some work just fine and some are completely broken.
Undocumented engine entities
Entities dumped by the dumpentityfactories
console command that don't exist in any official FGD or map. Some may be non-functional or buggy.