Find your niche.
From that music bit in Jellicent's sig, I could say I adore Shizui's Gym track. Definitely one of my favourite renditions of the Gym theme. It's just so chill and relaxing. Which is really fitting for the Water-type theme of the Gym, and it kind of gives a tropical or beach vibe. :)
I generally love the soundtrack so far, though! Still new to the vocals because my only experience with that would be Ghetsis' Theme from BW but I think I'll manage.