shouldn't have
might or may have
would have
must have
can't have
should have
could have
used to express what was possible in the past
used to say that sth was a good idea, but we didn't do it
used to say that sth wasn't a good a idea, but we did it
used to express that sth happened (or not) in the past as a result of sth else
used to say that we had the opportunity to do sth, but we didn't
used to express conclusions about the past
used to conclude that sth was impossible in the past