BLearning, Knowledge & Data
109 sitesB
MMolView
FreemiumSketch molecules and view them as interactive 3D models with spectral data
molview.orgVisit
MMatrix Calculator
FreeCompute determinants, inverses, eigenvalues, and decompositions of matrices online
matrixcalc.orgVisit
TToned Ear
FreeTrain your ear on intervals, chords, scales, and progressions for free
tonedear.comVisit
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Mmusictheory.net
FreeLearn music theory with free interactive lessons, exercises, and ear trainers
musictheory.netVisit
EExplorable Explanations
FreeLearn through play with a curated hub of interactive explanations
explorabl.esVisit
SSaylor Academy
Free160+ free self-paced courses with certificates and credit recognition
learn.saylor.orgVisit
SShortcutFoo
FreemiumMaster keyboard shortcuts for VSCode, Vim, Figma and 30+ tools with spaced repetition
shortcutfoo.comVisit
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OOur World in Data
Free14,000+ interactive charts on 126 topics under an open license
ourworldindata.orgVisit
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WWordReference
FreeMultilingual online dictionary and forum strong on examples and idioms
wordreference.comVisit
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GGeoGebra
FreeIntegrated math visualization tool for geometry, algebra, calculus and statistics
geogebra.orgVisit
FfreeCodeCamp
FreeFree coding curriculum, projects and certifications (nonprofit)
freecodecamp.orgVisit
OOpen Culture
FreeCurated free courses, audiobooks, documentaries and e-books from around the world
openculture.comVisit
IInformation is Beautiful
FreeCases that turn the world's data into infographics
informationisbeautiful.netVisit
EEtymonline
FreeScholarly etymology dictionary tracing English word origins and shifts in meaning
etymonline.comVisit
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IInternet Archive
FreeDigital library preserving books, video, music and web snapshots
archive.orgVisit
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TThe Pudding
FreeInteractive visual essays combining data visualization and storytelling
pudding.coolVisit
GGapminder
FreeTools to correct global misconceptions with data (bubble charts, Dollar Street)
gapminder.orgVisit
WWorld Bank Open Data
FreeFree development and economic indicators for 217 countries
data.worldbank.orgVisit
SStandard Ebooks
FreePublic domain e-books with polished proofreading and typesetting
standardebooks.orgVisit
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WWolfram Alpha
FreemiumKnowledge engine that answers natural-language questions with computation and data
wolframalpha.comVisit
BBrilliant
FreemiumInteractive courses that teach math, science and CS through problem-solving
brilliant.orgVisit
PPublic Domain Review
FreeUnearthing out-of-copyright sources with essays and 10,000+ public domain images
publicdomainreview.orgVisit
OOldMapsOnline
FreeBrowse 500,000+ historical maps by place and time, overlaid on modern maps
oldmapsonline.orgVisit
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GGoogle Dataset Search
FreeSearch that finds public datasets across the web
datasetsearch.research.google.comVisit
SStanford Encyclopedia of Philosophy
FreeFree peer-reviewed encyclopedia of philosophy
plato.stanford.eduVisit
SSeeing Theory
FreeProbability and statistics through interactive D3 visualizations (Brown University)
seeing-theory.brown.eduVisit
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MMonkeytype
FreeMinimal, customizable multilingual typing practice measuring WPM and accuracy
monkeytype.comVisit
OOmniglot
FreeEncyclopedia of the world's writing systems, languages and multilingual phrases
omniglot.comVisit
LLibreTexts
Free2,000+ free open textbooks across 17 fields plus a homework system
libretexts.orgVisit
PPhET
FreeInteractive physics, chemistry and math simulations from CU Boulder (Korean)
phet.colorado.eduVisit
TTatoeba
FreeOpen database of 13.5M example sentences and translations in 429 languages (audio, API)
tatoeba.orgVisit
MMathigon
FreeExplore math through interactive courses and the Polypad virtual manipulatives playground
mathigon.orgVisit
LLanguage Transfer
FreeAudio language learning by the 'Thinking Method' (no ads, sign-up or fees)
languagetransfer.orgVisit
OOneLook
FreeDescribe a concept in plain words to find the exact word across 800+ dictionaries
onelook.comVisit