Crossword puzzle clue "like most mail"

Like express mail vis-à-vis regular mail

"The most-played, most-imitated, most influential puzzler of all time," per the video game website IGN

Forgets to mail the mail, say

They come after signatures in snail mail, yet before signatures in e-mail: Abbr.

___ mail (e-mail folder)

___ mail (e-mail alternative)

Like most mail

Most junk mail