Of course this list is only of the ones I know about, so if you know of another Khan scream besides the original from WoK let me know. Another note, is that this list does include the various incarnations of the scream that substitute the word Khan for something else. Examples might include Spongebob Squarepants "PRRAAAAAAWWN" or The Big Bang Theory "WWWWWWWHHHHEEEEAAATTTTTOONN!"
The Long Khan was started by EPIX and was an effort to create the longest Khan scream in existence. All you have to do is upload your Khan scream and they edit it into the ever growing video. There have also been organized events held with William Shatner to get the most people in one place doing the Khan scream into the world record books. For 31 years, this 2 second clip has been inspiring people across the globe to yell at the top of their lungs. Do not worry fellow fans, Zachary Quinto won't be the last to take it on.
1) Fanboys -Seth Rogen (no video) Sorry, I guess no one thought it good enough to post on Youtube.
2) The Critic -Maurice LaMarche: In the Critic, LaMarche was often tasked with impersonating Shatner and in this clip he uses the Khan scream in a parody of Rescue 911.
3) Family Guy -Seth McFarlane: In another parody, McFarlane voices Shatner performing Fiddler on the Roof and he blurts out the scream a little into his scene.
4) Mortal Kombat vs D.C. Universe - Richard Epcar: Fans of the old Mortal Kombat games will appreciate this entry by Richard Epcar. He voices Raiden and Joker in this game from 2008. One of the main villains is named Khan and Joker has some fun by doing his best Khan scream during some dialogue with other characters.
5) Futurama -William Shatner: Yes, even the man who made the line famous has gone one to have a little fun with it.
6) Robot Chicken -Seth McFarlane: Seth is at it again, lending his Kirk to a skit called 2 Kirks a Khan and A Pizza Place.
7) Seinfeld -Jason Alexander: This entire episode revolves around Jerry quoting Star Trek II to the Ross family who have just loss their daughter. Here's a six minute clip that has all the Star Trek goodies in it, including Jason Alexander's epic Khan scream...which I dare say is the best of all the screams.