Here you can download Microsoft Agent characters from Dropbox. Those characters were copied from Bellcraft's website, in this case, if the website ever goes offline. Once downloaded, open the package file and read the readme.txt file.
Bear in mind that there are no previews for characters on this website and so may either contain some good or bad animations. If there is a character that you don't like, just unpack another character. There is also a credit to the animators and companies.