AZ's Floette (eternal flower Floette) is an unused variation of Floette owned by AZ that has appeared in the coding in every single main title Pokémon game released for the 3DS, but has never been used outside it's model.
It has a unique stat spread different from a regular Floette focusing more on offense and speed.
It was originally believed to have been a Pokémon to be distributed during the XY years, but generation 6 came and went, the rumoured Pokémon Z never happened ect. It's overall purpose remains unclear, it is likely that it was only intended for a boss fight with AZ that included Floette in his roster.
That of course never happened either.
In Ultra Sun and Moon it has it's own unique Pokedex entry despite never being obtainable legitimately.