J.D. Bengtson

Deciphering the narrative of the human family

Merritt Ruhlen

Tower of Babel

The website of modern Nostraticists in the line of Sergei Starostin, with many interactive maps of language families and phyla and a host of interconnected etymological databases 

Digital Dictionaries of South Asia

eDictionaries for modern literary languages of South Asia.

Nuristan – Hidden Land of the Hindu Kush

Richard Strand's database on Nuristani and neighboring languages 

Roger Blench website

Data (often rare) on many African and other languages, original comparative studies by the author 

Monumenta Altaica

Grammatical, lexical and comparative data on Altaic languages (including Korean and Japanese) 

University of Texas Linguistic Research Center

A complete course in Indo-European comparative linguistics, including complete courses in nearly every IE branch (from Hittite to Sanskrit through Avestan, Greek, Germanic, Slavic, Tocharian and Armenian) 

Ethnologue

A detailed database of all living languages, with a moderately conservative classification: Nostratic/Eurasiatic or Amerind are not included, but Niger-Congo, Nilo-Saharan and Australian are; very detailed linguistic maps 

Lexilogos

Rich lexical and grammatical resources on over a hundred languages; virtual keyboards for non-Latin languages

Structure and Dynamics

eJournal of Anthropological and Related Sciences (eScholarship – University of California)