Ask Lemmygrad

Just looking for people whose works I should read as I dive deeper into marxism, and want to see a relatively diverse amount of perspectives so I don't become biased towards one marxist tendency or another. Mattick was recommended to me for their book "Marx and Keynes: The Limits of the Mixed Economy" but I wonder if I'm getting ahead of myself if I read that, since so far I've only read "Principles of Communism" by Engels, and "Blackshirts and Reds" by Parenti (which I especially liked for being engaging) so far. I'd also appreciate any other suggestions or reading lists!