Critics in the vein of Sontag, Barthes, Benjamin, Steiner etc.

There is a certain stylistic reason about their writing that really strikes a chord. But also their perspectivism. Barthes with his concept of pleasure, of eroticism, of texts that follow a doctrine of hedonism, for example, truly is one of a kind. The same goes for Sontag or Walter Benjamin or Adorno or George Steiner or Jacques Derrida or Lacoue-Labarthe or Kristeva or Blanchot or Bakhtin and so on. They are not usual, dogmatic critics, even if some of them had come up with a dogma of their own, but even so, they still acted like insurgents, like iconoclasts that really could not fit in a very large branch. For example, Adorno and Steiner and Derrida and Lacoue-Labarthe have all written about Paul Celan, about his obscure verses, about the difficulty that his poems reclaim. They weren't dull and boring, they always managed to give birth to a new point of view, as Barthes argued that this should be the critic's main aim: to bring to light new meanings. And I was wondering, what would be a list of those strange, unclassifiable literary spirits? What I'm looking for is the courage to break the lines, to transgress the limits imposed by previous critics; a kind of rapturous energy that burns like phosphorus--I'm looking for critics that could get obsessed by their subject and wrote full-out, indefatigable, unafraid, in a very personal, idiosyncratic manner; critics that are inimitable, that, perhaps, would've been enthralled by Celan's hermetic formulae.

Not a critic per se but William Blake

I think William Blake might be a very interesting and not too far fetched proposal. Mainly because he has so many dimensions, like a gem with many facets. He was interested in so many domains, and he did not refrain himself from getting involved in so many domains, in spite of not having the required professional training. Like Barthes or Paul Valéry, it's hard to believe that they had thorough knowledge of everything they wrote about. And yet, they did write about so many things, they did show an indefatigable curiosity that spread over any domain. In a sense, perhaps what I'm looking for is dilettants. Dilettants of immense talent who were not ashamed to manifest their interest in everything that kindled a thought in them. It's all a search for infinite imagination and energy.

Based on your criterion of "critics that could get obsessed by their subject and wrote full-out, indefatigable, unafraid, in a very personal, idiosyncratic manner" I would submit Harold Bloom, Sigmund Freud, and Leo Tolstoy. Although, based on some of your other preferred attributes ("infinite imagination and energy"), I would submit Umberto Eco and someone like Slavoj Žižek, although he is a philosopher and not a literary critic per se. There's also Georges Bataille, to extend your French list.

Bataille, of course, he was very energetic, and also very unstable. One of his collection of writings is called, if I remember correctly, Visions of Excess. Just the perfect title to define Bataille, a man for whom something had to be watched upon in the light of an excess in order for it to be of any value. He was cranky, unhinged, lacking any balance--and this is precisely why he is so fascinating, for of course he has a lot of charm, but I think he is too brutal to be put in the same bracket with Barthes. They both talked about pleasure, but for Bataille pleasure was mostly rape, while for Barthes it was jouissance. From the same generation as Bataille there is also Simone Weil, again, a very fascinating appearance, sick and maddening. It's about zeal, I think, about fervor. Simone Weil, as Bataille, excelled in this domain. Their books burn at cosmogonical temperatures. Yet, I'm looking for something more refined, and more obscure. Someone that's not too well known in the literary landscape. Someone that has yet to meet his followers.