omnicalculator.com

A huge collection of calculators from several Fields like Biology, Physics, Constructions,… to help you get to the right result

libraryofbabel.info

The Library of Babel is a place for scholars to do research, for artists and writers to seek inspiration. The library is basically just a huge collection of random text, but you can search it for patterns theoretically, it contains everything which has ever been written, or ever will be written

desmos.com

Desmos offers best-in-class calculators, digital math activities, and curriculum to help every student love math and love learning math.

thistothat.com

Check whether you can glue certain things to other things. Recommends a glue.

sci-hub.se

Sci-Hub is the most controversial project in modern science. The goal of Sci-Hub is to provide free and unrestricted access to all scientific knowledge.