indian giver an offensive term for someone who asks you to return a present he has given you
altruist,
philanthropist someone who makes charitable donations intended to increase human well-being
settlor,
trustor (law) a person who creates a trust by giving real or personal property in trust to a trustee for the benefit of a beneficiary; a person who gives such property is said to settle it on the trustee
contributor,
subscriber a writer whose work is published in a newspaper or magazine or as part of a book
