This is a Wild Area event held by Sword and Shield. This event hosts Taurus, Miltank and Bouffalant, to celebrate the Lunar New Year of 2021.
The Pokémon were all ox-like species, as this year is known as the Year of the Ox, as per the Chinese Zodiac Calendar.
This event also has an increased chance of landing a Shiny Tauros.
To import these files into your save, use PKHeX's block importing function. Our tutorial should guide you through it.
Our first post of this page contains some data relevant to the importing stage.
There's info and some common questions regarding Wild Area Events here.
To see other Wild Area Events, here.