Copy and paste whole layers with ⌘C/⌘V (no selection), within a project and between projects, keeping editable text, masks, effects and folders. ⌘J, Paste and Option-drag duplicate every selected layer, stacked together above the topmost; ⌘J also duplicates folders. A right-click menu in the Layers panel. 3:4 and 9:16 crop ratios. With a selection, the crop tool starts at its bounds.