The New Atheism movement comes to mind. You could call that a large scale coalition towards progressive reform in the area of religion and atheism. Is that what you mean?
Richard Dawkins is probably the most well-known advocate of that movement, but other prominent names include Daniel Denett, Sam Harris and Christopher Hitchens.
“I’m wondering if it is possible for mankind to have it’s own moral codes & convictions without the belief in a God.”
Well, that’s a separate question, and the answer is unequivocally yes, of course we can. Many of us already live this way, myself included.
Morality and ethics aren’t all that complicated, once you get rid of a lot of nonsense¹. My own two golden rules are “don’t be a jerk” and “make people happy”. Work towards those concrete goals and you’ll be a good person no matter what you think the fundamental nature of the universe is.
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¹ I unapologetically believe it is nonsense, for example, to believe things can be inherently right or wrong, as opposed to being subjectively perceived that way; and I also consider it nonsense to believe it’s important to cleave to abstract principles even when their concrete consequences lead to a decrease in people who are happy. These are not necessarily popular points of view.