Archive of back issues of Eureka, the recreational mathematics journal of the Cambridge Archimedeans, now online for open access: https://www.archim.org.uk/eureka/archive/, via https://aperiodical.com/2021/02/aperiodical-news-roundup-january-2021/

On Wikipedia, the popular articles from Eureka appear to be Dyson's work on ranks of partitions, in #8, Haselgrove & Haselgrove on polyominoes, in #23, Penrose on pentaplexity, in #39, and Leinster on his eponymous groups, in #55.