Here are some of my favorites from YouTube.
Techno Transformershttp://www.youtube.com/watch?v=IdDeVnytZ6U"This vid is exactly what the title says! It is composed of various clips from Transformers Galixy force, Generation 1, Armada, Energon, and Beast Machines! This was a request done for a friend! The song is "Help Me" by Kelis."
Optimus Dance http://www.youtube.com/watch?v=yoI-UaMOV64"I made a papermache Optimus Prime suit for Halloween and thought it would be good to make a video of myself dancing to Daft Punk."
Beast Wars Megatron Had the Worst Luck http://www.youtube.com/watch?v=EZd8zQkaTbE"Gotta give him points for effort, with less resources, and either retarded or backstabbing henchman, he still gave it his all.
He just had bad luck. Hard to have good luck when everyone thinks you're a Drag Queen."
Beast Wars: Waspinator's Destruction Clips Season 1 http://www.youtube.com/watch?v=UvLwUuTfdew"These are clips of Waspinator getting destroyed from Season 1 of Beast Wars."
(There is also a compilation video for Season 2 by the same person.)Transformers Teaser Trailer (Titles Re-edit) http://www.youtube.com/watch?v=05BFqg9ktWg"Fan made teaser trailer for the upcoming live action Transformers movie being released on July 4th, 2007. (Titles Re-edit)"
(This may have already been linked here, but I don't recall. Sorry.)SuperNews! - Transformers 2?http://www.youtube.com/watch?v=gGQsthDNGW0"What would a good movie be without a sequel? Shortly after the release of Transformers, director and producer Michael Bay tries to talk the Transformers into doing a sequel."
(This is for an older audience. My apologies if this has already been linked.)