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Saint Augustine, an African theologian who was one of the most significant post-Biblical Christian thinkers in the early church, was heavily influenced by Plato. His descriptions of God the Father can be connected directly with Plato's Form of the Good, an immaterial, eternal, perfect entity that is the source of all good within the universe.
Given the shaping impact of this line of thought on the church, you might, in some sense, say that we are all Platonists.
With that said, I am not aware of any denomination or sect that specifically adapts the rest of Plato's theory of the Forms to Christian belief.