probably about 2-3 dozen actually. I made a list once.

Nondenominational, Baptist, Southern Baptist, Church of Christ, Church of God, Pentecostal, Assemblies of God, Presbyterian, Reformed, Evangelical, Missionary, Methodist, Lutheran, Charismatic, Messianic, Amish, Mennonite, Nazarene, Brethren, Apostolic, Full Gospel, Episcopalean, Weslyan, Seventh Day Adventist, Coptic, Catholic, Eastern Orthodox....

and then basically if you fall well outside of those few main, essentially bible-believing, groups, pretty much the only ones who consider you christian are your own group and you end up fighting about it with everyone else.