Pressing F12 shows or hide the dashboard.
If you have a lot of unused keyboard shortcuts yourself and would like to replace their functions with something that you actually use, below is a guide on how to remap keys on your Mac. When Apple designed the MacBook keyboards, they were probably thinking of which commands we will be using the most when they assigned shortcuts to specific functions, but as with everything else that is being used by millions of people, actual usage does not always align with intended purpose, so many default keys are left unused while some missing keys remain desired.