Applescript code completion shortcut

Question

You can use Script Assistant's Auto-Completion with the Esc key.

One can also use ctrl+[ instead (which generates the same key sequence), especially for touch-bar users who do not have a physical Esc key.

It probably changed whith sierra or High-Sierra :

It's now option + escape keys.

Personally, I don't like the Escape key to auto-complete. To add your own key to auto-complete, go to System Preferences > Keyboard > Shortcuts > App Shortcuts and add an entry for Script Editor named Complete. You can then choose your own shortcut to auto-complete in the Script Editor.

I use Cmd + D. Of the keys you tried, only Shift + Arrow works.