Website initiated by Ken Knabb and dedicated to the Situationist International (1957-1972) and Guy Debord in particular. Includes the full text of many documents and an extensive further bibliography

Perspectives on politics and society from the viewpoint of the Global South

Interesting collection of texts on liberty and associated topics from all periods, assembled by the Liberty Fund.

International collaborative research project exploring 20th century anti-colonial, anti-imperial and related left periodicals of the Global South. Outputs include a directory of key publications, browsable by geography, date, theme, language

Large archive in Nottingham on the anarchist movement in the UK and beyond, with a focus on radicalism in Nottingham and the E. Midlands. Some materials digitised, see:
https://archive.org/details/sparrowsnestlibrary?tab=collection

The Frantz Fanon Foundation is an international network faithful to the values ​​of Frantz Fanon and his rebellion against colonialism in all its forms

Some online resources plus further links.

The Bodleian Library (University of Oxford) has digitised John Locke's journal

Aims to make freely available the full text of his works (in French)

Its library offers full text access to key writings of the 19th & 20th centuries & includes lesser known writers. Also see extensive list of newspapers & periodicals available digitally. See also the International Institute of Social History (Amsterdam) which has digitised papers of Marx & Engels from its SPD archive.