Danish:

• https://ordnet.dk/
• https://hu.bab.la/sz%C3%B3t%C3%A1r/angol-d%C3%A1n/
• https://hu.bab.la/sz%C3%B3t%C3%A1r/d%C3%A1n-n%C3%A9met/
• http://udtaleordbog.dk/
• http://schwa.dk/

Norwegian:

• https://ordbok.uib.no/
• https://www.naob.no/
• https://hu.bab.la/sz%C3%B3t%C3%A1r/angol-norv%C3%A9g/

Swedish:

• https://svenska.se/
• https://www.saob.se/
• http://kaino.kotus.fi/fsob/
• https://hu.bab.la/sz%C3%B3t%C3%A1r/angol-sv%C3%A9d/
• https://hu.bab.la/sz%C3%B3t%C3%A1r/sv%C3%A9d-n%C3%A9met/

Faroese:

• https://sprotin.fo/

Greendlandic:

• https://oqaasileriffik.gl/en/dict/
• http://www.ilinniusiorfik.gl/oqaatsit/daka

Icelandic:

• https://idordabanki.arnastofnun.is/
• https://islex.arnastofnun.is/dk/
• https://www.ordabok.is/
• https://snara.is/
  
  A more comprehensive list is available here here.

litteraturbanken.se (Swedish literarure)
adl.dk (Danish literature)
runeberg.org (Scandinavian literature)
dokpro.uio.no/litteratur (Norwegian literature)
skandinaviske-oversaettelser.net (Ancient and Medieval literature in Scandinavian translation)
https://www.idunn.no/ (research database – journals on Scandinavian Studies)
http://www.emroon.no/MenotaBlitz.html (a digital tool for the short-hand transcription of primarily Old Norse source material)

https://nordics.info/
norden.org

• Danish
  dr.dk
  politiken.dk
  information.dk
  jyllands-posten.dk
  berlingske.dk

• Swedish
  sverigesradio.se
  svt.se
  aftonbladet.se
  dn.se
  svt.se

• Norwegian
  nrk.no
  aftenposten.no
  vg.no

• Icelandic
  mbl.is/frettir/
  ruv.is

• Faroese
  dimma.fo/
  kvf.fo/

• Greenlandic
  sermitsiaq.ag/
  https://knr.gl/da/knr-t

Norwegian:

Norsk grammatikk kort forklart: https://grammatikk.com/

Store norske leksikon: https://snl.no/

Språkrådet: https://www.sprakradet.no/

Nasjonal digital læringsarena: https://ndla.no/

Manusbanken: https://www.manusbank.no/index.php?view=writerList&letter=i#main

Swedish:

Glosbe: https://hu.glosbe.com/

SFI: https://sfipatxi.

SFA: https://swedish-for-all.

Danish:

Dansk Sprognævn: https://dsn.dk/

Det Danske Sprog- og Litteraturselskab/DSL: https://dsl.dk/

De Danske Sprogcentre. https://www.dedanskesprogcentre.dk/

Den Store Danske: https://denstoredanske.lex.dk/Danmark_-_sprog

Sproget: https://sproget.dk/

Metodebogen: https://metodebogen.dk/

Manuscripts in the Royal Library: http://www5.kb.dk/da/nb/materialer/haandskrifter/HA/e-mss/index.html

Danish Embassy in Budapest: https://ungarn.um.dk/en/

Hungarian Embassy in Copenhagen: https://koppenhaga.mfa.gov.hu/

Swedish Embassy in Budapest: https://www.swedenabroad.se/hu/embassies/magyarorsz%C3%A1g-budapest/

Hungarian Embassy in Stockholm: https://stockholm.mfa.gov.hu/

Norwegian Embassy in Budapest: https://www.norway.no/en/hungary/ 

Hungarian Embassy in Oslo: https://oslo.mfa.gov.hu/