Some key alternative media publications, which you could keyword search via the following Lakehead links are:
Lakehead also has access to Independent Voices, via JSTOR. Please note the "late 20th century" time-coverage in the description below.
Independent Voices is an open access digital collection of alternative press newspapers, magazines and journals, drawn from the special collections of participating libraries. These periodicals were produced by feminists, dissident GIs, campus radicals, Native Americans, anti-war activists, Black Power advocates, Hispanics, LGBT activists, the extreme right-wing press and alternative literary magazines during the latter half of the 20th century.
The following resources are available freely on the internet. Please check this Queens University page for Indigenous media sources in Canada. This (Canadian) independent media list is from the Sandy and Nora podcast. Please check this library page from Sacramento State which lists key U.S. alternative media magazines which publish online.