This isn't actually unusual in the grand scheme of things, just at the moment. "Libertarian" was originally a word that anarchists came up with to describe themselves for a good reason. Lysander Spooner is famous in right-wing libertarian circles, but the guy also promoted mutualism and was the member of the First International. Today, what you describe goes under the label of "libertarian free-market socialism".
Regarding regulation, I do have to note that in many cases when you try to root-cause corporate power, it turns out that it hinges on active government regulation in practice. For example, consider the fundamentals of capitalism, namely, accumulation of capital. Why do we get those huge monopolies in the first place? Well, because more capital means more way to generate wealth (or, more precisely, to appropriate wealth generated by your workers), which can be invested into more capital etc - there is a natural positive feedback loop here. So at a first glance it feels like you need government to actively do something to prevent companies from becoming too large. But consider: what does it mean for a company to own something? It's not a person, so it can't really have physical possession of things. It's all abstract property rights, and the only reason why that works is because the society as a whole acknowledges those rights and legitimate, and, crucially, because there is a state providing infrastructure (police, courts etc) to enforce them. Now imagine what would happen if, for example, the state simply refused to acknowledge property rights past a certain limit and simply wouldn't enforce them on behalf of the property owners.