Who are the Great Tribulation Saints?

The Great tribulation period is the period of time that comes after the tribulation period.

There are those who are saved during the great tribulation period as well.

The Great Tribulation period is worse than the Tribulation period.

Who are the Great Tribulation saints?
*Gentiles-from every nation, kindred, people, and language
*They are clothed in white robes, and have palms in their hands.
*They stand before the throne, and before the Lamb.
* They cry with a loud voice, saying "Salvation to our God which sitteth upon the throne, and unto the Lamb."
* "...These are they which came out of great tribulation,and have washed their robes, and made them white in the blood of the Lamb."
* Where is this found?
* In the New Testament part of the Bible!
* In Revelation 7:9-10,14-17