BASE is one of the world's most voluminous search engines especially for academic web resources. The index contains more than 400 million records from more than 11,000 content providers. You can access the full texts of about 60% of the indexed records for free (Open Access). BASE is operated by Bielefeld University Library.

Science.gov provides access to millions

of authoritative scientific research results from U.S. federal agencies.

 Bioline International is a not-for-profit scholarly publishing cooperative committed to providing open access to quality research journals published in developing countries. BI's goal of reducing the South to North knowledge gap is crucial to a global understanding of health (tropical medicine, infectious diseases, epidemiology, emerging new diseases), biodiversity, the environment, conservation and international development. By providing a platform for the distribution of peer-reviewed journals (currently from Bangladesh, Brazil, Chile, China, Colombia, Egypt, Ghana, India, Iran, Kenya, Malaysia, Nigeria, Tanzania, Turkey, Uganda and Venezuela), BI helps to reduce the global knowledge divide by making bioscience information generated in these countries available to the international research community world-wide. 

RefSeek is a web search engine for students and researchers that aims to make academic information easily accessible to everyone. RefSeek searches more than five billion documents, including web pages, books, encyclopedias, journals, and newspapers.

RefSeek's unique approach offers students comprehensive subject coverage without the information overload of a general search engine—increasing the visibility of academic information and compelling ideas that are often lost in a muddle of sponsored links and commercial results.

Internet search engine for text-oriented websites. Indexing the small, old and weird web.

Links to websites that work well on basic web browsers including those that come with e-readers.

mu is a tool for dealing with e-mail messages stored in the Maildir-format, on Unix-like systems.

Curlie strives to be the largest human-edited directory of the Web. It is run by volunteer editors. Join today to add to our collection or create your own!

We started as the Open Directory Project (ODP), later became DMOZ, and In 2017, we launched Curlie to continue the 100% free directory. There is no cost to submit a site to the directory or use the directory's data.

A cursory review of all the non-metasearch, indexing search engines I have been able to find.