I don't see a keyboard shortcut for "Open Folder..." listed on the documentation page below, and after searching elsewhere for a while I didn't see anything else.
https://code.visualstudio.com/docs/customization/keybindings
I thought I would ask here before putting an issue on GitHub about it. (Also there doesn't seem to be a open / closed issue about this anywhere on the GitHub repo.)
There is indeed a shortcut for it, the command is workbench.action.files.openFolder, and the default keybinding is Ctrl+K,Ctrl+O.
It's easy to find in the list of shortcuts (File → Preferences → Keyboard Shortcuts) if you search for "folder" or "openFolder" in the Default Keybindings.
Hit Cmd+O on macOS or Ctrl+O on Windows/Linux to activate the open dialog, select a folder, and click "Open."
Note: This answer was written before multiple folder workspaces were implemented in VS Code. If you open folders this way, it will replace your entire workspace with the folder you selected to open. If you want to add a folder to your existing workspace, you must use Cmd+K, Cmd+O on a macOS or Ctrl+K, Ctrl+O on Windows/Linux.
You have to type Ctrl+K and then Ctrl+O to open a folder in Vs code on Windows and you have to type Cmd+K and Cmd+O to open folder in Vs code on mac...
