Besides the Worldwide Church of God, which started as a cult under Herbert Armstrong and has since pretty much joined the mainstream of orthodox Protestant evangelicism, there are:
The Church of God (Cleveland, Tennessee), started 1886 as a holiness movement in the Southeast, became Pentecostal in 1896, is now a mainstream Pentecostal denomination and the oldest Pentecostal denomination in the world.
The Church of God of Prophecy (also based in Cleveland), a splinter group from the CoG.
The Church of God (Anderson, Indiana), a non-Pentecostal but fairly fundamentalist denomination known for having produced musicians like Bill Gaither and Sandi Patti.
…just to name a few. What you’re seeing in Missouri is probably the Cleveland CoG.
DaveBj