Big B shared this with us in microsoft.public.word.newusers:

I am considering upgrading to work pro If receive more fonts in that
version than the one I have in the word of the home edition.

I'm quite sure the number of fonts is constant.

If you are looking for additional fonts, click the following link:
http://www.google.com/search?q=download+truetype+fonts
Some of them are free (gratis) or even Free (libre).

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Amedee Van Gasse