Much like the game Favimon is based on, Favimon have a small chance of appearing as Shiny.
However, Shiny Favimon will have a non-cosmetic benefit, in this case 1 extra Action slot.
Shiny Favimon will have a sparkling animation on their favicon while in combat.
Here are the 4 actions of the Shiny class that are currently known.
Please add more to this list to keep it updated.
Every Favimon has a chance of being Shiny when encountered.