John Steinbeck’s later years are probably at least problematic, but i think The Grapes of Wrath is excellent and it doesn’t get brought up discussing socialist literature. It’s an amazing book just due to the writing but it touches on a lot of core socialist values, the oppression of the proletariat, capitalist destruction of the environment, the need for solidarity, etc. When i bring it up most people wave it off as a book they had to read in school I read it on my own in my twenties and it’s still one of my favorite books with Flowers for Algernon.