This is what I got as a reply for one of my cold emails -
I appreciate you have attempted to reach out to me repeatedly. At XYZ, we keep all
our development in-house and within Canada. Due to tax incentives, it does not make financial
sense to outsource any of our development outside our country.
I wish you the best of luck and request that you discontinue sending me marketing emails.
So much better than "Fuck off/STOP SPAMMING ME/Take me off your list".