When in doubt, try Wikipedia.
For history, mythology, and video game design:
For engineering:
For linguistics:
For science:
For spaceflight:
- Brilliant: learn to think
- Feedly: Google Reader replacement
- Google Books: all the books, scanned
- Google Patents
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- Internet Archive
- Librivox: free, public domain audiobooks
- MasterClass: learn from the best
- Open Culture
- Open Textbook Library
- Project Gutenberg
- ScienceDirect
- Skillshare: explore your creativity
- TimeTree: the timescale of life
- Wikidata: free knowledge base
- Wikipedia: free-content encyclopedia
- Wikisource: free-content library
- Wikispecies: directory of species
- Wikiversity: free learning materials & activities
- City Beautiful
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- The Finer Points
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- Crafted Workshop
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- Hardtail Party
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- Pinkbike
- Seth's Bike Hacks
- Skills with Phil
- TheUselessTrials
If you need equipment, see the music starter kit.
- Aimee Nolte Music
- Composerily - Music Theory The Basics
- Learn music theory in half an hour
- The Circle of Fifths made clear
- Michael New
- Paul Davids
- Polyphonic
- Pogo
- Professor of Rock
- Scott's Bass Lessons .com
- Scott's Bass Lessons on YouTube
- Yale Music Theory Course
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- in / development
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- Luke Seerveld / Meet the Gaffer
- Mark Bone
- Nerdwriter1
- Spenser Sakurai
- Wandering DP
- wolfcrow
- 365 Data Science
- Corey Schafer: Pandas Tutorials
- freeCodeCamp.org: Data Science
- Propagate Knowledge
- TEDx: Data Science
- Real Python
- Socratica
- Corey Schafer
- The Mighty Dictionary
- Transforming Code into Beautiful, Idiomatic Python
- iBiology
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- Joe Scott
- Kurzgesagt – In a Nutshell
- Mark Rober
- minutephysics
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- WikiTongues