Dictionaries, Encyclopedias & Digital Libraries

• Lexilogos
  Estonian-English Online Dictionary
• Institute of Baltic Studies' English-Estonian Dictionary
• Forvo Pronunciation Dictionary
  Crowdsourced guide to pronunciation of Estonian words
• Eesti Keele Instituut Estonian Dictionary
• Dictionary of Estonian Language
• Estonian Etymological Dictionary
• Thesaurus 
• Slangi Dictionary of Estonian Slang
• Voro-Eesti Synaraamat
  Dictionary of the dialect of Voru in southeast Estonia
• Estonica
  Encyclopedia about Estonia

Grammar

• List of Country Names in Estonian
• CoolJugator: Estonian Verb Conjugator

Vocabulary

• Omniglot 
  Introduction to Estonian, with guide to alphabet and basic phrases
• SpeakLanguages
  Basic phrases and vocabulary in Estonian
• WikiTravel 
  Estonian phrasebook

Reading & Writing

• The Little Prince in Estonian 

Listening & Speaking

• Estonica: Orthography and Pronunciation Guide
• Forvo Crowdsourced pronunciation dictionary by native Estonians

Online Course Materials

• Keeleklikk
  Online course for beginners
• I kinda like languages
  Five introductory Estonian lessons
• Live Lingua Project
  Introductory online lessons in Estonian through the Peace Corps

News & Media

• Estonian Folk Songs
  PDF Archive of old Estonian folktales
• delfi.ee
• postimees.ee
• ohtuleht.ee
• elmar.ee
• kuku.ee

Arts, Films & Music

• Literature
  Classic Estonian literature with translations in French
• Kalevipoeg by Friedrich Kreutzwald
• Writing from the Edge
  Introduction to Estonian literature in English translation