Safari can do some pretty useful stuff with bookmark folders. For example, if you have a folder in your Favorites Bar at the top of the window, hold ⌘ (Command) when you click it to open all of that folder’s bookmarks in a group of tabs. To create a new folder in your Favorites Bar, right-click it or use Bookmarks > Show All Bookmarks and use the buttons around the window there.
This can be useful if you have a group of sites you typically check in the morning, or sites you open when starting a certain kind of work; having Safari open them all at once for you is convenient, and it saves some time, too.
- go to Bookmarks > Show All Bookmarks
- click the Bookmarks Bar section in the sidebar
- in your list of bookmarks in the center of the window, toggle the Auto-Click option next to a folder
Lastly, in Safari’s Preferences > General pane, you can change the “New windows open with” option to any of your bookmark folders. This will open a group of tabs for that folder every time you start Safari or use ⌘-N to create a new window.