Well, on the UK side of things you can probably pick any of the authors published during Michael Moorcock's tenure at New Worlds: so Aldiss, Moorcock, M John Harrison, Hilary Bailey, Ballard, Barrington J Bayley, Disch, Brunner.

You can also probably toss in Delany, Spinrad, much of Dangerous Visions, and then go on from there.

The movement, if there was one, is best characterised by a shift from puzzle stories to more complex fiction, with some authors crossing the divide, like Silverberg and Zelazny in the US.