Wikipedia - Wikipedia is a free online encyclopedia, created and edited by volunteers around the world and hosted by the Wikimedia Foundation.

Mendeley - Easily organize your papers, read & annotate your PDFs, collaborate in private or open groups, and securely access your research from everywhere.

WikiTribune - Evidence based journalism, from the founder of Wikipedia

Zotero - Zotero is a free, easy-to-use tool to help you collect, organize, cite, and share research.

Wikiverse - An interactive galaxy of Wikipedia knowledge ✨

Qiqqa - Qiqqa is a free research and reference management software. It can be used in many organizational projects from the academic to the personal to the business endeavor. Read more about Qiqqa.