From Bulbapedia, the community-driven Pokémon encyclopedia.
Emily (Japanese: エミリ Emily) is a character of the day in the Pokémon anime who appeared in Wherefore Art Thou, Pokémon?. Her Japanese voice actress is 雪乃五月 Satsuki Yukino and her English voice actress is Amy Birnbaum.
Emily lived on Mandarin Island South with her Nidoran♀, Maria. While living on the island, she had an ongoing rivalry with Ralph. Both of them always competed with each other to see who had the best Pokémon. Somehow, they always ended up getting the same Pokémon until Emily obtained Maria and Ralph obtained his own Nidoran♂, Tony. Although the two humans couldn't stand each other, their Nidoran fell in love.
Misty thought that Ralph and Emily truly loved each other deep down, so she tried to get them together. However, all she ended up doing was driving a bigger rift between them. They only decided to stop hating each other when their Nidoran were kidnapped by Team Rocket. Emily and Ralph teamed up to stop Team Rocket and get their Pokémon back.
After saving their Nidoran and seeing how much they loved each other, Ralph and Emily decided to put aside their differences and let Tony and Maria see each other. The two Nidoran, happy with their owners' decisions, kissed and promptly evolved into Nidorino and Nidorina.
This listing is of the known Pokémon owned by Emily in the anime: