The implementation of keyboard shortcuts for autofilling of credit cards and identities are now needed more urgently, since the newest UI redesign pushes many card and identity items off the screen in the Tab view, requiring extra mouse manipulations to scroll the view before one can select an item to autofill.
I have also identified the following Feature Request threads, which are asking for essentially the same functionality:
Autofill [and shortcut] of Identity or Cards
Keyboard shortcuts for fill in default CARD / IDENTITY
May we have two new keyboard shortcuts?
These should be merged.