The legends over at Scape Forums have a thread where they share and host scans of old 'zines. Unlike the Archive.org hoard, this collection largely IS visual kei and there's plenty of good shit in there. Have a look and be sure to thank them for all their hard work! https://www.scapeforums.com/index.php?threads/the-magazine-project.6179/

For the unaware, Archive.org has a number of scanned issues of various music magazines, including SHOXX, Fool's Mate, Rockin'F, and more. It's not an incredibly fleshed out collection but if you're looking for something in particular, it's a great first place to start. https://archive.org/search?query=subject%3A"magazine"+subject%3A"music"+subject%3A"japanese"