Wallhacking
Wallhacking allows a player to see through solid or opaque objects and/or manipulate or remove textures, to know in advance when an opponent is about to come into targeting range from an occluded area. This can be done by making wall textures transparent, or modifying the game maps to insert polygonal holes into otherwise solid walls.
ESP
Extrasensory perception, often read incorrectly as "Extrasensory precision" (ESP) in video games displays contextual information such as the health, name, equipment, position and/or orientation of other participants as navigation/directional markers, which would normally be hidden from game players. This may be performed by reading the program's memory with an external program, or intercepting and decoding packets as they travel between the client and the server, or else by reading the memory arrays containing player positions. The advantage of such a cheat is that it would allow the user extensive information about their opponents, allowing for selection or avoidance of less or more dangerous opponents, respectively. This is extremely difficult to detect and prove, but is definitely considered cheating.
