I want to say Palette, I really do, but Suisei, Mori and Watame all got original songs that fit them so well, meanwhile it feels like Towa is still trying to find herself.
Also I like Reflect and Sparks was really cool, even if Kiara said she felt weird going that far out of her comfort zone.
For the sake of the thread, I'll give it to Ai Mai Chocolate.
https://youtu.be/P8OjkcLzYCM