The Moon receives most of its light from the Sun, either directly through sunlight or indirectly through Earthshine. However, there are many other dimmer sources of illumination.
Starlight. This is probably the most important one. Under exceptional conditions, it creates shadows here on Earth.
Artificial light. Mostly city lights and gas flares.
Meteorological activity. Lightning storms on Earth and other planets are visible from space, and here on Earth, they can trigger other sources of light such as firestorms.
Bioluminescence. Light-emitting microorganisms are bright enough and numerous enough to be seen from space.
Transient bright lights. Events such as supernovas and asteroid impacts are rare, but when they happen, they are a significant source of illumination. Over long timescales, for example a billion years, this may be the biggest contributor of non-solar light.
How much do these light sources illuminate the Moon? If there was no Sun, could we still see the Moon with these lights? And of the three Earth-based sources (artificial light, meteorological activity, bioluminescence), which one illuminates the best?