It's hard to answer this question because libertarians and socialists are like water and oil. That said, things like the end of intellectual property and abolition of the police are points that I see both sides agreeing (there might be more points, but I can't remember right now).

The problem is that aside from a few of the original writers (like Mises or Hayek, examples from the top of my head), most libertarians out there on par, or even more than tankies in their fanatism. But maybe that's a problem with most big movements anyway.