When you've got a great worldview just sitting there being all great, lit critics are like, "Hey, why not apply it to art?" So Hegel is part of a long tradition of philosophers whose work has been used to critique literature. 

Aristotle

You could call him the original gangster of blending a philosophical outlook with aesthetic criticism. Plato started this mix off with some beauty talk, but Aristotle pushed it to the next level in his Poetics. Scholars still reference how he defines the major poetic (and dramatic) genres of tragedy and comedy.

Immanuel Kant

Kant's aesthetics rest on refining one's judgment, and having a disinterested engagement with a work of art. Yeah, we think he's a bit pretentious, too. Nonetheless, his Critique of Judgment stands as the starting point for people who want to assess what's actually good art. Love him or hate him, you can't escape Kant.

Michel Foucault

Foucault is really, really into power. More specifically, he's into figuring out who has power, why, and how power shapes the course of history. He definitely dabbled in a little lit crit of his own, but it's his texts on the ways of the world that scholars so often refer to when exploring literature today. From Discipline and Punish to The History of Sexuality, he's a one-stop shop for reading up on the ways people dominate others.