The World Radio History site has historic amateur radio magazines from UK, Australia, New Zealand and USA in PDF format. Titles include Ham Radio Today, Amateur Radio, Short Wave Magazine, Practical Wireless and QST.

Example: The Ham Radio Today magazine archive at https://worldradiohistory.com/Ham_Radio_Today.htm

The Internet Archve hosts amateur radio publication PDFs such as the popular 73 Magazine 1960-2003

The Digital Library of Amateur Radio and Communications is a library of materials and collections related to amateur radio and early communications. The DLARC is funded by a significant grant from Amateur Radio Digital Communications, a private foundation, to create a digital library that documents, preserves, and provides open access to the history of this community.