In episode 43 of Naruto Shippuden, there is a song that is not included (I think) in any of the OSTs. When Naruto
is stabbed by Orochimaru's long sword and
crashes onto rocks, this song plays when Sakura sees Naruto's fox form.
Also, that song or a similar one can be heard in episode 166 when
Hinata is stabbed by Pain
which makes Naruto rages
I think it can also be heard in episode 258 or 259 when
Kisame got interrogated and they almost learned who the guy who calls himself "Uchiha Madara" is.