Final answer:
Richard Strauss is the composer who fits the description provided, known for his rich harmonies and contributions to Opera in the post-Romantic era, inspired by Wagner and Verdi.
Step-by-step explanation:
The composer who contributed to Opera, drew inspiration from Wagner and Verdi, was drawn to storylines with exotic settings, embraced new instruments, and enlarged the size and configuration of his orchestra, with harmonies rich with chromaticism, is Richard Strauss. Strauss was a key figure in the post-Romantic era, pushing the boundaries of Romantic musical techniques to their limits and was influenced by the progressive works of his predecessors. His operas and other compositions often featured large orchestras and complex harmonies, drawing from various cultures and settings for inspiration. Notable works by Strauss include 'Thus Spake Zarathustra', which was used famously by director Stanley Kubrick in the film '2001: A Space Odyssey'