First you need to understand that there is no organization called "Grace Community Churches".
Every local church named, "Grace Community Church" is a separate entity not related, except by Jesus, with the others.
So there is no denomination named that.
And unlike one of the people who replied to this question citing thousand of denominations, in reality there are about 500 to 600 different Christain denominations in the world.
The reason some groups claim there are over 30,000 denominations is that they count the same group again each time it appear in another state or another country.
Now about the other part of your question, let me share this:
Prior to the 1500's the corrupt Roman Church was about the only church in Europe and they claimed to be the only true church. They did not allow the Bible to be translated into the common language of the common man and when others tried to this such as William Tyndale and Martin Luther, they tried their best to have them murdered.
Once the printing press was invented and people like Luther and Tyndale and Wycliffe translated the Bible in common languages such as German and English, people could, for the first time read the Bible for themselves.
Most learned from reading the Bible that the Roman church wasn't following the Bible so they began to start churches in their own countries and each evangalical church started up in a different European country got translated into a different protestant denomination in the USA today.
So the word "Protestant" applies to any non Roman Catholic group which protested against the Roman Catholic Church.
Examples of that would be Lutheran, Presbyterian, Methodists, Baptists, etc.
As men freely read the Bible, groups would get togher and decide, "You know what the most important thing the Roman Catholics are doing wrong, is baptizing babies, we need to start Baptizing only adults after they have been born-again."
That group of people came to be known as Baptists.
The group in Germany which followed Martin Luther's teachings were called Lutherans.
The group in England who preferred the methodology of John and Charles Wesley were called Methodists.
One group believed the most important thing was that the local church should be ruled by local Elders instead of the Pope. Since the word in the Bible translated into the English as Elders, was the Greek word "presbyterous" they became known as Presbyterians.
Since you mentioned Mormons, they were started by a man named Joseph Smith who claimed to be prophet and who claimed all othe churches were wrong and claimed that God had told him that each man should have more than one wife.
The main difference between Cathlics and the groups are that Roman Catholics believe Peter founded their church and that they wrote the Bible and that they alone have the right to interpret the Bible.
The rest of the Bible-believing groups believe that Jesus founded the church and not Peter, and that the rules for running the church are in the Bible and the Holy Spirit wrote the Bible and not the church, so that church can and should only do what the Bible says they can.
I fall into this latter group.
We believe the Bible is God's Word and it is our only and absolute authority on all issues of faith and morals and practice.
We believe Jesus sent the Holy Spirit to lead the church on earth in His absence.
If you have any more questions, feel free to ask.
Pastor Art