C207 pilot reported alternator failure inflight.

Narrative

During a scheduled flight from ZZZ to ZZZ1; I noticed my marine VHF radio suddenly turned off. I scanned my instruments and noticed that my fuel gauges; CHT gauge; oil pressure gauge; and oil temp gauge were all erratic and atypical. Additionally; my ammeter was indicating a discharge. Suspecting an alternator failure; I followed the guidance in the airplane's POH. No circuit breakers had popped; and cycling the master switch did not resolve the discharge. I made a radio call on company frequency seeking guidance; and made the decision to turn back towards ZZZ. Another pilot stated they would relay my intentions to ZZZ Tower. Shortly after turning back; my radio displays and GPS displays began to flicker. At this time; I turned the master switch off in hopes that I could conserve battery life. When I went to turn it on again a few minutes later; it was dead. I proceeded towards ZZZ class D airspace; scanning for traffic constantly. Upon arrival; I circled the airport at 2000 MSL in hopes that I would see light gun signals. After approximately 10 minutes of circling; I hadn't seen any signals; so I waited for the airport surface to become clear of traffic and entered the pattern. I flew a left pattern for Runway XXL and landed shortly after a light airplane had departed. I taxied into the company ramp and shut down.