Right-click any viewport label. > Views > Choose a perspective or orthographic view.
Right-click any viewport label. > Views > Grid > Choose any grid view.
Select a shape. > Right-click any viewport label. > Views > Shape
Keyboard > V (to open the Viewports quad menu), then P (Perspective), U (User), F (Front), K (Back), T (Top), B (Bottom), L (Left)
Perspective, orthographic, user, grid, and shape viewports all share the same viewport controls.

Perspective and orthographic viewport controls include the following. Two of these controls are available in all viewports.
Zoom Extents / Zoom Extents Selected (available in all viewports)
Arc Rotate, Arc Rotate Selected, Arc Rotate Sub-Object
Maximize Viewport Toggle (available in all viewports)