There are several free encyclopedias available online that provide access to a vast amount of information across various topics. Some of the most notable ones include:

1. Wikipedia: Wikipedia is one of the largest and most comprehensive online encyclopedias, offering articles on a wide range of subjects in multiple languages. It is a collaborative platform that allows users to create, edit, and contribute to articles, making it a dynamic and continuously updated resource.
2. Encyclopedia Britannica: Encyclopedia Britannica offers a free version of its online encyclopedia, providing access to a selection of articles, images, and videos on various topics. While not as extensive as its premium subscription service, the free version still offers valuable information and resources.
3. Columbia Encyclopedia: The Columbia Encyclopedia is available online for free through various sources, including websites and digital libraries. It offers concise and authoritative articles on a wide range of subjects, including history, geography, science, and literature.
4. Stanford Encyclopedia of Philosophy: The Stanford Encyclopedia of Philosophy is a freely accessible online encyclopedia that provides in-depth articles written and reviewed by experts in the field of philosophy. It covers a wide range of philosophical topics, theories, and thinkers.
5. Internet Encyclopedia of Philosophy: The Internet Encyclopedia of Philosophy is another free online resource that offers articles on philosophy and related disciplines. It provides peer-reviewed entries written by experts and covers a wide range of philosophical topics and traditions.
6. Infoplease: Infoplease is a comprehensive reference website that offers free access to encyclopedic content, including articles, maps, and timelines, covering a wide range of subjects such as history, geography, science, and current events.
7. Citizendium: Citizendium is a collaborative online encyclopedia project that aims to provide reliable and accurate information on various topics. It incorporates elements of traditional encyclopedias along with a collaborative editing model similar to Wikipedia.

These are just a few examples of the many free encyclopedias available online. While these resources offer valuable information, it’s essential to critically evaluate the credibility and reliability of the content, as well as to cross-reference information with other sources when necessary.