If you're interested in phenomenology and/or existentialism and works that are somewhat readable (this is subjective of course), I'd suggest: 1. Maurice Merleau-Ponty - The Phenomenology of Perception 2. Simone de Beauvoir - Ethics of Ambiguity 3. Friedrich Nietzsche - Will to Power I'd highly recommend NOT reading Being and Time by Heidegger - you'll want to stab your eyes out ten times. Outside of pure philosophical texts and more emphasis on fictional works related to philosophy, I'd suggest indirect material that encourage ideas of subjective perception and point-of-view. Examples are works by Franz Kafka, Ryu Murakami and William S. Burroughs.
Also recommended in this reply