What functions are restricted to administrator accounts?

Dave R.

OK, to keep me from banging my head against the wall any more than I
have to, can anyone point me to a definitive list of those things that
are restricted to administrator users only? Not those that are
restricted to administrator users by default (although that would be a
nice list to have as well), but those things that there is no way to
assign to a non-administrator.

Regards,

Dave