By "switch rack" do you mean electrical distribution panel? There are lots of "extras" that you might want to include but the standard set of circuit breakers pretty much has to be installed in a row and right next to each other.
Other things you might want to include:
amps gauge either the panel amps or remote reading type to see all the loads. Note that some loads and all sources do not go through the panel so a remote reading unit can show the batteries charging where a panel amps meter will not.
volts gauge with selector switch so you can see the house or start batteries even if they are isolated
clock
12 volt outlet (cigarette)
Labels for the boat bridge clearance, draft length and width
AC amps and volts
a nav station light, fixed or removable depending on where the panel actually is in relation to the nav station desk