[elliottcarlson]

You should also check out Phrack Magazine (an online distributed ezine that is still active, albeit with years between issues - they also have a 2024 call for writers though!) at phrack.org

Another older print publication was Blacklisted! 411, very similar format to 2600. I attended some meetups from both of these back in the day.

[plapsley]

If you want something really ancient, check out YIPL/TAP, which was the first phone phreak newsletter (started publishing in May 1971) that was the granddaddy of 2600. You can get it on the Internet Archive: https://archive.org/details/YIPLTAP_1-91