Deleuze's books on history of philosophy are interesting and approachable. Although they are more about his own philosophy over people he write about they're still very valuable. Deleuze gets bad reputation for his other writings as they are difficult to read but that's not the case with books on history. He also have books on Nietzsche so that might be a nice starting point. Other continental philosophers that you could try are Heidegger, Foucault or Bataille. Everything depends on what you're looking for, but if you're coming from Nietzsche and Stirner they might be interesting for you.

Edit: As someone else mentioned, Walter Benjamin is also very interesting!