Country music comes in many forms and hybridizes with every other sort of music. Since I am typing this particular post from Lafayette, Louisiana, let’s start with Cajun music. The Early Cajun Music blog is your best resource for learning about the history of Cajun music. The first Cajun records were made in the 1920s and there has been cross-pollination with country music ever since, but there are no Cajun musicians in the CMHOF. I have seen Cajun greats like Doug Kershaw and Jo-El Sonnier in recent years. Jimmy C. Newman was a member of the Grand Ole Opry from 1956 until his death in 2014, one of the longest memberships in Opry history.
Louisiana has many regional musical styles and they often overlap. For instance, I went to the 50th annual Frog Festival in Rayne, Louisiana a few days ago. Mathew Ewing is billed as country, Sharona Thomas as soul, and Ryan Foret as swamp pop, but they all had similar instrumentation (keyboard, electric guitar and/or bass, drums, saxophone) and covered a variety of styles.
Tejano and related styles of music also frequently overlap with country. I live in central Texas, where there is a sizable Latino population. Covers of Freddy Fender and Johnny Rodriguez show up in every sort of music in Texas, from mariachi to polka. You’ll hear Tejano musicians cover Hank Williams and Johnny Cash and Willie Nelson and other classic country artists, too. If Texans had a vote, Freddy Fender would have been in the CMHOF long ago.
There are natural crossovers among all types of accordion music, too. Polka, cajun, zydeco, Tejano, and Norteño bands will throw in bits of the other styles. Josh Baca and the Hot Tamales often cross zydeco with conjunto. The accordion used to be much more common in mainstream country music than it is now. Look back at old clips from the fifties and you’ll see everyone from Roy Acuff’s band to the Carter Sisters with accordions.