Here Paul calls the true gospel “the gospel of Christ”.
“There are some who trouble you and want to pervert the gospel of Christ”. Galatians 1:7.
In other places in the New Testament it is called the gospel of Jesus Christ.
“The beginning of the gospel of Jesus Christ, the Son of God. Mark 1:1”.
“Those who do not obey the gospel of our Lord Jesus Christ. 1 Thessalonians 1:8”.
“I am not ashamed of the gospel of Christ, Romans 1:16”.
In the gospel writings it is the phrase “the gospel of the kingdom” that we read of.
I believe the greatest title is the gospel of God. This comes seven times in the New Testament. Here are some occurrences:
“Paul, a bondservant of Jesus Christ, called an apostle, separated to the gospel of God, Romans 1:1”.
“That I might be a minister of Jesus Christ,… ministering the gospel of God…. Romans 15:16”.
“Even after we had suffered … we were bold in our God to speak to you the gospel of God….
1 Thessalonians 2:2”.
“We were well pleased to impart to you, not only the gospel of God, but also our own lives, because you had become dear to us, 1 Thessalonians 2:8”.
“What will be the end be of those who do not obey the gospel of God? 1 Peter 4:17”.