Project Gutenberg
Project Gutenberg is a library of over 75,000 free eBooks
https://www.gutenberg.orgWikipedia
the free encyclopedia that anyone can edit
https://en.wikipedia.org/Etymology Online
Online dictionary of etymology
https://www.etymonline.comLibriVox
Free public domain audiobooks. Read by volunteers from around the world.
https://librivox.orgPetrucci Music Library
Free sheet music PDF downloads.
https://imslp.orgPlane Finder
Live air traffic, find any flight
https://planefinder.net