AnonymousHi,
"In her will, it was requested that most of her estate go to animal charities"
You are talking about property, not anything countable, and therefore a singular verb is needed: Most of her estate goes to animal charities. If the reference were to something countable, a plural verb would be needed: Most of these books are interesting. Most of those boys know the answer. Most of them are happy. But: Most of it is easy.
CB