Dictionary and language in context
http://www.linguee.co.uk/
Linguee is a bilingual dictionary + a linguistic corpus
Spell checks
http://ludwig.guru/
Ludwig is a smart translator and linguistic search engine
Machine translation
http://www.elanlanguages.com/en/free-translation
Machine translation tool
Language learning
http://learn.lindsaydoeslanguages.com/
very useful and affordable online language courses
Linguistic research
http://www.webcorp.org.uk/live/guide.jsp
World Wide Web as a corpus
http://www.dwds.de/?qu=hallo
German digital corpus
Linguistics communites
http://linguistlist.org/indexfd.cfm
Terminology resources
https://www.microsoft.com/language/en-us/default.aspx
Microsoft language portal
https://data-app.taus.net/
TAUS terminology search