Is there a guide how to identify connectors?
There is no simple “one-stop shop” for identifying connectors.

The motor cycle manufacturers are liable to use different connectors to the car manufacturers as there is likely to be more exposure to the elements.

So, basically different industries different connectors - the choice or design of a particular connector will depend on its function, space available, ambient conditions (wet, dry, corrosive, heat/cold cycles etc), amount of use - disconnected often or never...