During the Credits
There are no extras during the credits of Tenacious D in The Pick of Destiny.
After the Credits (spoilers)
There is an extra scene that shows Kyle and JB sitting around a tape recorder in their apartment. JB tells Kyle not to make a sound unless it’s a masterpiece. Kyle asks how will he know if it’s a masterpiece. JB says he’ll feel it, and if he feels it, to lay it on him. They sit there in silence until Kyle acts like he’s about to say something, but ends up just farting. Kyle tells JB that he thought he felt something. JB then says, “Lets hear that back.”