I always liked how Gen 5’s music can get me really pumped during battles, it’s probably the “drums”.
My favorites are the elite 4 theme which conveys the raw power of those trainers:
https://youtu.be/llnXhrCn9YoThen the plasma grunt theme which would honestly be a good fit for any boss fight:
https://youtu.be/pF1n0GflZMgAnd the non-box legendary theme which perfectly emulates the jumps in excitement as you weaken the legendaries and throw balls at them:
https://youtu.be/ks-mBWcDRgc 
