During a fire is no time to find out that the extinguisher will not function because it is out of date. A paddle is required, not optional equipment, and again should be in a convenient and accessible location. Deployment of the anchor should occur at the first sign of trouble to keep your boat in its present safe location. Too often then anchor is the last thing thought of and boats end up drifting into dangerous situations. Some sort of bailing device should be on board.
Pumps are useless when the battery goes dead.
The one flaw in flashlights is that they seem to fail just when we need them. A radio with weather band capability is not only recommended for day operation but is an essential piece of equipment at night. Those clouds that look harmless that you see floating over can be hiding a serious storm. First aid kit, basic tools, manuals etc. are all recommended on board Navigation tools, which are helpful in the daylight, become absolutely essential for safety at night. Obviously your best choice for nighttime operation would be a GPS .