8. Eddie Guerrero - Crackin'
There's an unfortunately morose reason this track was forgotten - it was only used for about a month and a half before Eddie's untimely death.
Guerrero first came out to "Crackin'" (sometimes called "Gangsta Lean") in early September of 2005. This reggaeton-inspired number reworked the instrumentation of the heel theme he'd debuted earlier in the year and featured the rap stylings of Kemo the Blaxican. As Guerrero progressively drifted further from his heelish antics, he would eventually re-adopt his more iconic theme that October. Two weeks later, he was gone.
WWE likely would have reused this theme had they turned Eddie heel once again, but unfortunately, we'll never know for certain. Rest in peace, Eddie, and Viva la Raza.