pikachu_upper_shell.stl and pikachu_lower_shell.stl for a split-shell design.
If the zip contains very small files (under 1KB), they may be Pokémon save data files for tools like Project Pokémon . Pikachu - Ball.zip
button_and_ring.stl for the functional or decorative center button. pikachu_upper_shell
If this report is instead for an inventory of physical "Pikachu & Ball" sets, note the following popular models: Pokémon TCG: Pikachu & Eevee Poké Ball Collection Pikachu - Ball.zip
Import the files into "slicer" software (like Cura or PrusaSlicer).
Ensure the design is "layered" if you intend to cut different colored vinyl for the Pikachu and Poké Ball elements. :