Yes, the one thing we can all agree on is the right to self. Nobody other than themselves can control their body - by that I mean that no matter what you do, nobody can tell you what to think. You can be brainwashed by force, or conditioned to react a certain way to escape force, but you can never really know what another person thinks.

Regardless, one has a right to their body. It is their property. More explicitly, any individual intelligent agent that exists takes up some physical space and that space they occupy at any point in time to continue their existence is theirs only. Property can be given up voluntarily or if nobody else has a claim to it - in this case it extends that clearly rape is wrong, but prostitution is okay, as it's voluntary on both sides. Seizing someone's house is wrong, but exploring space and building new structures in the middle of nowhere is not.

Whether laws exist regarding private property (or the lack thereof), we can define a set of natural rights that any person has regardless of any local, regional, or global laws, constructs, or ideologies. We can all agree murder is wrong, rape is wrong, stealing is wrong, slavery is wrong, and the clearest and most concise way of setting this forward is by understanding that nobody is entitled to anything other than their body and any property they have gained which was either unclaimed or voluntarily from another agent.

Certain schools of thought disagree on unclaimed property, e.g. if one settles a piece of land and the landowner doesn't notice, but after a decade or so has passed and the resident has worked the land and only then the landowner notices, who really owns it? I am not in a position to answer this but I don't think it's "arbitrary" or "man-made" to expect natural rights over your body and property. Everything else, indeed, is abstract.