There are at least 5 “Church of God” denominations that I have had contact with.
Church of God (Cleveland Tenn.). The Pentecostal church of God
Church of God (Anderson, In.) The Holiness church of God
Church of God, Evening Light— More “Keswick” in it’s theology, similar to Anderson (Fun fact, my former C&MA church may have been influenced by this movement prior to it’s contact with the C&MA, they are quite similar)
Church of God, Restoration-A plain dressing cult that avoids medical care, and is very “One true Church” in its outlook.
Church of God. (Mennonite) - The Holdeman group.
I hope this answers your questions.