There are:
- The gospel of the kingdom
- The gospel of Jesus Christ
- The gospel of the kingdom of God
- The gospel of the grace of God
- The gospel of God
- The gospel of Christ
- The gospel of peace
- The gospel of the uncircumcision
- The gospel of the circumcision
- The gospel of your salvation
These are all the same Gospel, that promises pardon from sin, and eternal life by faith in the righteousness of Jesus Christ, which comes to sinners by the power of the Holy Spirit unto guaranteed salvation.
The Gospel is always the promise of forgiveness and everlasting life.
If the "news" does not contain God's Covenant promises of grace, it is NOT a gospel message.
The gospel of the kingdom was about the coming of the King to Israel to establish His righteous Kingdom. This is how the twelve could go to Israel and preach the gospel of the kingdom and still have no understanding that Christ would die.
Mat 10:5-7 These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not: (6) But go rather to the lost sheep of the house of Israel. (7) And as ye go, preach, saying, The kingdom of heaven is at hand.
Luk 18:31-34 Then he took unto him the twelve, and said unto them, Behold, we go up to Jerusalem, and all things that are written by the prophets concerning the Son of man shall be accomplished. (32) For he shall be delivered unto the Gentiles, and shall be mocked, and spitefully entreated, and spitted on: (33) And they shall scourge him, and put him to death: and the third day he shall rise again. (34) And they understood none of these things: and this saying was hid from them, neither knew they the things which were spoken.