Wayne's list is very helpful, but it would be nice if there was a domain we
could count on to have correct records that will be around for a
while. Seems like mipassoc.org should set one up.
My iecc.com has been around since 1993 and I don't expect to be going
away any time soon. I believe the CSV records are correct; if someone
finds a mistake I'll fix them.
By the way, there are also CSV records for iecc.com, mail.iecc.com, and
mail2.iecc.com, saying that none of them send mail, since they all are
forged in HELO from time to time.
Cheetahmail is a large ESP. I suspect they'll be around for a while, too.