I had a pleural effusion. i haven't gotten the full biopsy report back but it said "450cc of clear amber fluid removed" what does the "amber fluid" mean?

It's just the color of the fluid. Your clinical situation (symptoms etc), the biopsy result, plus lab tests on the fluid are necessary to even guess at the cause or treatment. You'll need to discuss it with your doctor.

If the pleural fluid isn't strictly straw colored it can be amber colored, deep yellow, because of infection, like TB or malignancy. The fluid will be cultured, cytology checked for malignant cells & often a biopsy.of the pleural lining is needed for diagnosis.

Wait for the biopsy report. amber fluid occurs often in benign conditions so that is a bit encouraging. Good luck.