As always, we'll go picture by picture to get a grasp on all the stuff we currently got, but firstly, let me quickly introduce her:

Sparkle/Hanabi is a member of The Masked Fools and shows it in her design with the incorporated mask elements, but she also has a lot of imagery that ties back to some fish species (maybe Betta Fish?). In short, her kit is focused on buffing HP, ATK and Skill Points.

Pictures 1 and 2: Character art (by stepleaker) and her character model (by JoQatwt)

Pictures 3 and 4: Assets tied to her (via otchims)

Picture 5: A frame from her Ultimate (via Blednaya)

Picture 6: Her base kit (via Mero) TL;DR: Her skill buffs HP and ATK. Her ULT provides 4 Skill Points, and if you have a full SP bar she can grant 2 extra temporary slots. Her talent buffs DMG per SP usage and her technique grants an extra SP.

Picture 7: Her signature Light Cone effects (via Affelious)

Pictures 8 and 9: Her voicelines (via stepleaker and translated by NathLWX)