This is a difficult question for me as I love country music. Some of my favourites are Garth Brooks, Kenny Rodgers, Johnny Cash, Lady Antebellum - just too many to list!
Am not a fan 'per se', but loved the music of Elvis, the Big O & Johnny Cash.
I believe the first two started out 'country' then moved from there.
I think Elvis was even a bit 'rockabilly' in the beginning!