There are two section of Cheats on Cheat Masters under the Cheat Tab above. There is a section for "submitted cheats" near the bottom that visitors have gave. These cheats are then voted on and if they are rated well then the cheat admin will move them to Verified cheats. These cheats are usually the most popular cheats that work or are the most helpful. So just scroll up for Half-Life: Opposing Force cheats
Lords of Legend RPG 
Where are Half-Life: Opposing Force Cheats?