Countrystartpage.com, Ranker.com and Wikipedia.org all publish lists of male country singers. Both the Country Start Page and Wikipedia have very comprehensive lists of male artists from the early days of country through the present, while Ranker focuses more on modern-day performers, as of 2015.
Another good resource for lists of male country artists is the Encyclopedia of Country Music. The Country Music Foundation compiled the book, which is over 600 pages in length and considered by millions of fans to be the authoritative historical and biographical work of the past eight decades of country music. It is available for purchase on the Country Music Hall of Fame and Museum's website, CountryMusicHallOfFame.com.