The Command key and the Globe key. Editing shortcuts (Cmd+C, Cmd+V, Cmd+Z, Cmd+B) match the Mac exactly, so Mac muscle memory transfers. The iPad-only actions live on the Globe key: Globe+H for Home, Globe+A for the Dock, Globe+C for Control Center, and Globe or Globe+E for emoji.
Screenshots and Markup. Cmd+Shift+3 takes a plain screenshot and saves it. Cmd+Shift+4 takes one and opens it in Markup right away, so you can crop or annotate before saving.
Window tiling. iPadOS 26 arranges apps as windows. Control+Globe with an arrow key tiles the current window to that half of the screen, and Control+Shift+Globe with an arrow places the current and most recent windows into two halves at once.