From what I have read, you can classify Christianity into four branches. The fourth branch would be called Restorationist.
Restorationists believe that the church lost it for 1900 or so years and that their sect represents the return of true Christianity. JW, Mormons, Adventists, United Pentecostals…etc. would all be considered restorationalists. Some restorationist we would consider Christian but a little wierd. Other restorationists we would consider not Christian.
If you are not Catholic, Orthodox, or Restorationist you would be considered Protestant.
Lutherans, Anglicans and Baptists are not Orthodox, Catholic, or Restorationalist (you might make a case that extreme KJV only Baptists though are Restorationists). The line might be considered blurry here.
Here is more information about restorationist.
Here’s a great breakdown:
Christian faith groups:
One source estimates that there are 34,000 separate Christian groups in the world.
We have attempted to sort them into:
Four to seven meta-groups, (Roman Catholicism, Eastern Orthodoxy, Protestantism…)
Three wings, (conservative, mainline and liberal)
Fifteen Religious families, (Adventist, Baptist, Lutheran, Reform…)
Dozens of denominations, (from the Amish to The Way), and
Many systems of belief (Arminianism, British Israelism, Calvinism…)
religioustolerance.org/christ.htm
Many hundreds of denominations: There are on the order of 1,200 Christian organizations in North America.
Their names range from the Amish to The Way.
We have essays describing some of them.
Four to eight meta-groups: Most of the Christian denominations and sects in the world can be sorted into about eight segments or branches: Roman Catholicism,
Eastern Orthodoxy,
Oriental Orthodox and Assyrian Churches,
Protestantism
Restorationists
Anglican Communion
Pentecostals
Others
Unfortunately, there is no consensus about which faith groups should be embraced by the term “Protestantism.” For example: Some theologians split out the Anglican Communion from Protestantism.
Others consider Pentecostalism to be separate from Protestantism.
Others separate the European Free-Church Family out as a separate group.
Some include the Restorationist denominations, which includes the Mormon church (a.k.a. LDS) within Protestantism. Some consider them to be a separate Christian group. Still others consider them to be non-Christian.
The organization Christian Churches Together (CCT), a broadly based, inclusive, Christian ecumenical movement, suggests still another classification of U.S. faith groups. They group Christian denominations into five families" Evangelical/Pentecostal, Historic Protestant, Historic Racial/Ethnic, Eastern Orthodox, and Roman Catholic.
Two or three “wings”: Like in the area of politics, Christians and Christian groups can be divided into conservative and liberal wings, according to their belief systems. Their teaching on abortion access, origins of the earth and the rest of the universe, equal rights for gays and lesbians, and same-sex marriage, are four indicators of their location on the liberal- conservative continuum. Fundamentalists, other Evangelical Protestants, Roman Catholics, and Eastern Orthodoxy, and such varied groups as the Jehovah’s Witnesses, Mormons, Unification Church, etc. generally form the conservative wing;
The Evangelical Lutheran Church in America, Progressive Christianity, Evolutionary Christianity, United Church of Christ, United Church of Canada and others form the liberal wing.
Often, a third, mainline wing is added, composed of such denominations as: American Baptist Churches in the USA, Presbyterian Church (USA), United Methodist Church, Episcopal Church, etc.
Fifteen religious families: Denominations can be sorted into 15 families, according to their historical roots. 1
Examples are the Adventist, Baptist, Lutheran, Pentecostal, and Presbyterian families.
Theological beliefs: There are many systems of theological beliefs within Christianity.
They often cut across denominational boundaries.
Members of an single congregation may hold conflicting belief systems.
Examples are Arminianism, British Israelism, Calvinism, Christian Identity, Universalism, etc.
The Barna Research Group, arguably the most important polling group working in the religious and spiritual area, sorts individuals into five faith segments according to their theological beliefs.
religioustolerance.org/christ7.htm