Downloading the latest Version from GitHub is still the prefered way to get MyPet. You can find the the latest version here: https://github.com/MyPetORG/MyPet/releases

Spigot only allows a limited file size for plugins, which MyPet unfortunately exceeds. Therefore, we have developed a downloader plugin that contains only the code to download MyPet itself. After the download MyPet will be loaded automatically as if you had installed it directly. This way, platforms like Aternos can also enjoy MyPet.