What follows was copy and pasted from the following web page link, that includes active links to each group that it mentions.
http://christianity.about.com/od/christiandoctrines/tp/denytrinity.htm
Mormonism - Latter-day Saints
Founded By: Joseph Smith, Jr., 1830.
Mormons believe that God has a physical, flesh and bones, eternal, perfect body. Men have the potential to become gods as well. Jesus is God's literal son, a separate being from God the Father and the "elder brother" of men. The Holy Spirit is also a separate being from God the Father and God the Son. The Holy Spirit is regarded as an impersonal power or spirit being. These three separate beings are "one" only in their purpose, and they make up the Godhead. More »
Jehovah's Witnesses
Founded By: Charles Taze Russell, 1879. Succeeded by Joseph F. Rutherford, 1917.
Jehovah's Witnesses believe that God is one person, Jehovah. Jesus was Jehovah's first creation. Jesus is not God, nor part of the Godhead. He is higher than the angels, but inferior to God. Jehovah used Jesus to create the rest of the universe. Before Jesus came to earth he was known as the archangel Michael. The Holy Spirit is an impersonal force from Jehovah, but not God. More »
Christian Science
Founded By: Mary Baker Eddy, 1879.
Christian Scientists believe the trinity is life, truth and love. As an impersonal principle, God is the only thing that truly exists. Everything else (matter) is an illusion. Jesus, though not God, is the Son of God. He was the promised Messiah but was not a deity. The Holy Spirit is divine science in the teachings of Christian Science. More »
Armstrongism
(Philadelphia Church of God, Global Church of God, United Church of God)
Founded By: Herbert W. Armstrong, 1934.
Traditional Armstrongism denies a Trinity, defining God as "a family of individuals." Original teachings say Jesus did not have a physical resurrection and the Holy Spirit is an impersonal force. More »
Christadelphians
Founded By: Dr. John Thomas, 1864.
Christadelphians believe God is one indivisible unity, not three distinct persons existing in one God. They deny the divinity of Jesus, believing he is fully human and separate from God. They do not believe the Holy Spirit is the third person of the trinity, but simply a force—the "unseen power" from God. More »
Oneness Pentecostals
Founded By: Frank Ewart, 1913.
Oneness Pentecostals believe that there is one God and God is one. Throughout time God manifested himself in three ways or "forms" (not persons), as Father, Son and Holy Spirit. Oneness Pentecostals take issue with the Trinity doctrine chiefly for its use of the term "person." They believe God cannot be three distinct persons, but only one being who has revealed himself in three different modes. It is important to note that Oneness Pentecostals do affirm the deity of Jesus Christ and the Holy Spirit. More »
Unification Church
Founded By: Sun Myung Moon, 1954.
Unification adherents believe that God is positive and negative, male and female. The universe is God's body, made by him. Jesus was not God, but a man. He did not experience a physical resurrection. In fact, his mission on earth failed and will be fulfilled through Sun Myung Moon, who is greater than Jesus. The Holy Spirit is feminine in nature. She collaborates with Jesus in the spirit realm to draw people to Sun Myung Moon. More »
Unity School of Christianity
Founded By: Charles and Myrtle Fillmore, 1889.
Similar to Christian Science, Unity adherents believe God is an unseen, impersonal principle, not a person. God is a force within everyone and everything. Jesus was only a man, not the Christ. He simply realized his spiritual identity as the Christ by practicing his potential for perfection. This is something all men can achieve. Jesus did not resurrect from the dead, but rather, he reincarnated. The Holy Spirit is the active expression of God's law. Only the spirit part of us is real, matter is not real. More »
Scientology - Dianetics
Founded By: L. Ron Hubbard, 1954.
Scientology defines God as Dynamic Infinity. Jesus is not God, Savior or Creator, nor does he have control of supernatural powers. He is usually overlooked in Dianetics. The Holy Spirit is absent from this belief system as well. Men are "thetan" - immortal, spiritual beings with limitless capabilities and powers, though often they are unaware of this potential. Scientology teaches men how to achieve "higher states of awareness and ability" through practicing Dianetics. More »
