Order 66 was a secret contingency order given to the Clone Troopers of the Grand Army of the Republic by Palpatine, which branded all Jedi as traitors to the Galactic Republic and ordered for them to be executed on sight.
Star Wars: Jedi Fallen Order
In JFO Cal Kestis is a Jedi Padawan whose master Jaro Tapal dies in his arms following an escape from a Venator class starship.
Star Wars: Battlefront II[]
In the Rise of Empire campaign, Operation Knightfall has you play as a member of Vader's elite group, the 501st Legion. As a member of the 501st, you hunt down the last of the Jedi in the galaxy and kill them.
Star Wars Episode 3: Revenge Of The Sith (Video Game)[]
In the mission titled "The Hunt Begins", Anakin Skywalker, now Darth Vader, leads the 501st Legion on a raid on the Jedi Temple, eliminating all Jedi inside starting with Jocasta Nu. The following mission, "The Final Lesson" has Vader duel Jedi Padawan, Serra Keto and her master, Cin Drallig.
Star Wars: The Force Unleashed[]
In the PSP version of the game, there is an arena-style mode "Order 66", where the player must survive an onslaught of various in-game enemies across multiple levels. Completing all waves unlocks the "Force Out" multiplayer mode, as well as Darth Maul as a playable character.