You can save libraries of colours as an Asset in Unity to be used in the Colour Picker. This is particularly helpful when using version control and syncing up with others working on the same project.
To save (or load) a colour library, you should expand the ‘Swatches’ section in the Colour Picker and click on the menu icon next to the header. From here you can change how you show your swatches (Grid/List), select libraries to load and create new ones.
When creating a new library, you can give it a name and specify where you want it to be created. If you use ‘Project Folder’ it will be local to the current project, helpful for version control! Preferences Folder’ will load for every project. A ‘Project Folder’ library will automatically be saved in the ‘Assets/Editor’ folder, and will create you a new one if one doesn’t already exist.
A loaded colour library will show all of your colours under ‘Swatches’ – you can only load one library at a time but can switch between them whenever you need.