The Index of Modernist Magazines provides factual information about the little magazines that fueled and broadcast modernism. You can access and learn more about many of these magazines in digital archives such as:
A joint project of Brown University and the University of Tulsa, The Modernist Journals Project (MJP) contains searchable and downloadable digital editions of over 30 modernist magazines, along with scholarly introductions and other helpful tools and information. The MJP’s December 1910 Collection is a great resource for exploring beyond little magazines.
The UK equivalent of the MJP, this website offers sample issues of magazines, an index, and other helpful information, along with related book projects.
This Princeton-based digital archive includes many European and American avant-garde magazines. It emphasizes international and experimental literary and artistic journals.
Begun in 1979 by the University of Iowa libraries, the International Dada Archive provides images, resources, and information about the Dada movement.
This virtual newsstand from the summer of 1925 gives you access to American popular and pulp magazines of the era.
The Beinecke Rare Books and Manuscripts Library is always adding to their searchable, digital collections.
Here’s a digital archive of the Marxist magazine The Liberator and another of the more general (if regional) interest magazine, Chicagoan (1926-1935). Time magazine and the New Yorker also have online digital archives.
Ron Unz has made lots of magazines available at UNZ.org – PDFs of everything from mass market to little magazines.