> Ctrl+a from my cold dead fingers

That conflicts with the standard Emacs binding to move to the beginning of the current line. Many years ago, I switched to C-z instead, on the theory that it is really easy to type C-z C-z when I really want to suspend whatever is currently running.

Pity that (AFAICT) terminals have no concept of Super and Hyper (USB doesn’t know about Hyper, either, but at least X11 does).