The purpose of this question is to link to various old (say $\succeq 1$ year old) closed posts, mostly by no longer active users, most of which are reasonable candidates for deletion, and a few for reopening, while it (in most cases) makes little sense to keep them closed and undeleted.
If you have enough reputation, you should be able to cast a deletion or reopening vote ($\ge 10000$ for deletion [needs 3 votes], $\ge 3000$ for reopening [needs 5 votes]). The deleting option is present under some conditions: for closed questions I think it's automatic if the score is $\le -3$, and in other cases depends on parameters (OP's rep? age of the question?) in some way I don't know (edit: some info here); also at $\ge 125$ reputation you can downvote, which in some cases can eventually lead to automatic deletion.
(I'd avoid here very active questions for which closure may have been disputed.)
I'll use answers to make such partial lists (usually of posts in a given subject, e.g., detected by some given tag). (Of course one can post "real" answers!) At some point I'll make updates indicating deleted/reopened questions, if applicable.