For me, Jake "The Snake" Roberts theme (the Snake Bit) is the best original wrestling theme ever!
It felt like a true wrestling theme. It also captured the 80's vibe as well. Somehow, I believe that the Snake Bit is the best original wrestling theme ever!
Another is Shinsuke Nakamura's The Rising Sun (NXT TakeOver Brooklyn version) and Stone Cold theme (I Won't Do What You Tell Me).