Some are not corpora, but (I think) they are corpus-related. The list is incomplete and just let me know if I omit any corpora.
1. The best corpora
COCA: http://www.americancorpus.org/
BNC-BYU: http://corpus.byu.edu/bnc/
TIME-BYU:http://corpus.byu.edu/time/
JustTheWord:http://193.133.140.102/JustTheWord/index.html
BNCweb:http://bncweb.lancs.ac.uk/bncwebSignup/user/login.php
Jukuu(句酷): http://www.jukuu.com/ for learners
Leeds: http://corpus.leeds.ac.uk/internet.html
Lextutor: http://www.lextutor.ca/
Web Concordancer: www.edict.com.hk
2. General Corpora
Jiaoda(上海交大): http://corpus.sjtu.edu.cn/WebCast/ click on “guest”
Brown/lob Corpus: http://www.lextutor.ca/concordancers/concord_e.html
Corpuseye: http://corp.hum.sdu.dk/cqp.en.html
Corpus swb : http://www.ldc.upenn.edu/cgi-bin/lol/swb/speechcorpus?&corpus=swb
BNC: http://www.natcorp.ox.ac.uk/ http://sara.natcorp.ox.ac.uk/lookup.html
Bank of English: http://www.collins.co.uk/Corpus/CorpusSearch.aspx
ANC: http://www.americannationalcorpus.org/OANC/index.html
ICE Corpora http://www.ucl.ac.uk/english-usage/ice/download/index.htm
3. English-Chinese Parellel Corpora(英汉双语语料库)
CEO:http://www.fleric.org.cn/ceo/
Babel:http://score.crpp.nie.edu.sg/cgi-bin/babel/paraconc.pl
The Dream Of Red Chamber(红楼梦): http://score.crpp.nie.edu.sg/hlm/index.htm
HK Poly U(香港理工大学): http://langbank.engl.polyu.edu.hk/Concordance/ParallelTexts/default.htm
Laozi(老子): http://score.crpp.nie.edu.sg/laozi/index.htm
Xiamen U(厦门大学): http://www.luweixmu.com/ec-corpus/query.asp
4. Textbook Corpora
College English:http://www.corpus4u.org/corpora/COLEN.rar
New Horizon College English(NHCE):http://www.nhce.edu.cn
New Concept English:http://luwei.2288.org/oechw/hanyu/data/CORPUS/nce/framconc.asp
Family Album USA: http://luwei.2288.org/oechw/hanyu/data/CORPUS/fam/framconc.asp
5. Business and Financial Corpora
Business English Corpus (BEC): http://users.utu.fi/micnel/BEC/
PolyU Business Corpus: http://langbank.engl.polyu.edu.hk/engine.aspx?Submit=Search&lang=1&corpus=30
Business Letter Corpus: http://www.someya-net.com/concordancer
Financial Corpus: http://langbank.engl.polyu.edu.hk/hkfsc/
6. Literary Corpora
The Online Corpus of Old English Poetry (OCOEP): http://www.oepoetry.ca/
Shakespeare's Sonnets Corpus: http://www.luweixmu.com/ecorpus/sonnets/framconc.asp
Blues Lyric Poetry Corpus: http://ota.ahds.ac.uk/ (search Catalog).
Canadian Poets Anthology Corpus: http://ota.ahds.ac.uk/ (search Catalog).
CAPA (contemporary American Poetry Archive): http://capa.conncoll.edu/
Claremont Corpus of Elizabethan Verse: http://ota.ahds.ac.uk/ (search Catalog)
Late Modern English Prose Corpus: http://ota.ahds.ac.uk/ (search Catalog)
New Dragon Book of Verse Corpus : http://ota.ahds.ac.uk/ (search Catalog).
Northwest Coast Indian mythology Corpus: http://ota.ahds.ac.uk/ (search Catalog).
Online Classics Horror and Phantasy Fiction: http://home.swipnet.se/~w-60478/
SETIS Australian Literary and Historical Texts: http://setis.library.usyd.edu.au/ozlit/
Corpus of Middle English Prose and Verse: http://www.hti.umich.edu/c/cme/
Harry Potter Corpus: http://luwei.2288.org/oechw/hanyu/data/CORPUS/harrypotter/framconc.asp
Towneley Plays Corpus: http://ota.ahds.ac.uk/ (search Catalog)
Web Concordances Site: http://www.dundee.ac.uk/english/wics/wics.htm
York Miracle Play Cycle Corpus: http://ota.ahds.ac.uk/ (search Catalog)
ME Texts Anthology Corpus: http://ota.ahds.ac.uk/ (search Catalog)
7. Web As Corpus
Web As Corpus :http://webascorpus.org/searchwac.htm
Web Corp: http://www.webcorp.org.uk/
WebCONC: http://www.niederlandistik.fu-berlin.de/cgi-bin/web-conc.cgi?sprache=en&art=google
8. Learner Corpora
Chinese Learners of English(中国英语学习者): http://www.clal.org.cn/corpus/EngSearchEngine.aspx
Corpus of Hungarian students' essays:
http://joeandco.blogspot.com/2008/06/writing-subcorpus.html
The Multimedia Adult English Learner Corpus:http://www.labschool.pdx.edu/maelc_access.html
The Uppsala Student English Corpus (USE):
Dowloadable data at http://www.ota.ox.ac.uk/headers/2457.xml
Michigan Corpus of Upper-level Student Papers: http://lw.lsa.umich.edu/eli/eli1/micusp/Contact.htm
IWILL Corpus: http://research.iwillnow.org/project/bncrce/default.htm
Wordneighbours: http://wordneighbors.ust.hk/
PICLE Corpus:http://ifa.amu.edu.pl/~kprzemek/concord2advr/search_adv_new.html
EVA Corpus: http://kh.hd.uib.no/eva/
PolyU Language Bank Concordancer:
http://langbank.engl.polyu.edu.hk/engine.aspx?Submit=Search&lang=1&corpus=16
The Montclair Electronic Language Learners' Database under construction)
http://www.chss.montclair.edu/linguistics/MELD/
Singapore Corpus of Research in Education:http://score.crpp.nie.edu.sg/score/index.htm
Birkbeck Spelling Error Corpus: http://ota.ahds.ac.uk/ (search Catalog)
Open Mind Commonsense Corpus: http://openmind.media.mit.edu/
Corpus for Higher Education:
http://langbank.engl.polyu.edu.hk/engine.aspx?Submit=Search&lang=1&corpus=11
National Taiwan Normal University Corpora:
http://llrc.eng.ntnu.edu.tw/English/search/Default.htm
http://llrc.eng.ntnu.edu.tw/English/search/tag.htm
http://llrc.eng.ntnu.edu.tw/English/search/tag2.htm
http://140.122.83.246/cwb/
http://140.122.83.246/cwb2/
ELISA corpus: http://www.uni-tuebingen.de/elisa/html/elisa_index.html
VLC: http://vlc.polyu.edu.hk/
9. News Corpora
Reuters Corpus: http://about.reuters.com/researchandstandards/corpus/
arpers Magazine 1879-1880 Corpus: http://ota.ahds.ac.uk/ (search Catalog).
Hong Kong South China Morning Post Corpus: http://ota.ahds.ac.uk/ (search Catalog)
New York Newspaper Advertisements and News Items 1777-1779: http://ota.ahds.ac.uk/
VOA Special English Corpus: http://www.manythings.org/voa/sentences.htm
VOA Special English audio and text corpus: http://www.dhytex.com/voanews.html.
American News Stories Corpus: http://ota.ahds.ac.uk/ (search Catalog).
MPQA Opinion Corpus: http://www.cs.pitt.edu/mpqa/databaserelease/
1. The best corpora
COCA: http://www.americancorpus.org/
BNC-BYU: http://corpus.byu.edu/bnc/
TIME-BYU:http://corpus.byu.edu/time/
JustTheWord:http://193.133.140.102/JustTheWord/index.html
BNCweb:http://bncweb.lancs.ac.uk/bncwebSignup/user/login.php
Jukuu(句酷): http://www.jukuu.com/ for learners
Leeds: http://corpus.leeds.ac.uk/internet.html
Lextutor: http://www.lextutor.ca/
Web Concordancer: www.edict.com.hk
2. General Corpora
Jiaoda(上海交大): http://corpus.sjtu.edu.cn/WebCast/ click on “guest”
Brown/lob Corpus: http://www.lextutor.ca/concordancers/concord_e.html
Corpuseye: http://corp.hum.sdu.dk/cqp.en.html
Corpus swb : http://www.ldc.upenn.edu/cgi-bin/lol/swb/speechcorpus?&corpus=swb
BNC: http://www.natcorp.ox.ac.uk/ http://sara.natcorp.ox.ac.uk/lookup.html
Bank of English: http://www.collins.co.uk/Corpus/CorpusSearch.aspx
ANC: http://www.americannationalcorpus.org/OANC/index.html
ICE Corpora http://www.ucl.ac.uk/english-usage/ice/download/index.htm
3. English-Chinese Parellel Corpora(英汉双语语料库)
CEO:http://www.fleric.org.cn/ceo/
Babel:http://score.crpp.nie.edu.sg/cgi-bin/babel/paraconc.pl
The Dream Of Red Chamber(红楼梦): http://score.crpp.nie.edu.sg/hlm/index.htm
HK Poly U(香港理工大学): http://langbank.engl.polyu.edu.hk/Concordance/ParallelTexts/default.htm
Laozi(老子): http://score.crpp.nie.edu.sg/laozi/index.htm
Xiamen U(厦门大学): http://www.luweixmu.com/ec-corpus/query.asp
4. Textbook Corpora
College English:http://www.corpus4u.org/corpora/COLEN.rar
New Horizon College English(NHCE):http://www.nhce.edu.cn
New Concept English:http://luwei.2288.org/oechw/hanyu/data/CORPUS/nce/framconc.asp
Family Album USA: http://luwei.2288.org/oechw/hanyu/data/CORPUS/fam/framconc.asp
5. Business and Financial Corpora
Business English Corpus (BEC): http://users.utu.fi/micnel/BEC/
PolyU Business Corpus: http://langbank.engl.polyu.edu.hk/engine.aspx?Submit=Search&lang=1&corpus=30
Business Letter Corpus: http://www.someya-net.com/concordancer
Financial Corpus: http://langbank.engl.polyu.edu.hk/hkfsc/
6. Literary Corpora
The Online Corpus of Old English Poetry (OCOEP): http://www.oepoetry.ca/
Shakespeare's Sonnets Corpus: http://www.luweixmu.com/ecorpus/sonnets/framconc.asp
Blues Lyric Poetry Corpus: http://ota.ahds.ac.uk/ (search Catalog).
Canadian Poets Anthology Corpus: http://ota.ahds.ac.uk/ (search Catalog).
CAPA (contemporary American Poetry Archive): http://capa.conncoll.edu/
Claremont Corpus of Elizabethan Verse: http://ota.ahds.ac.uk/ (search Catalog)
Late Modern English Prose Corpus: http://ota.ahds.ac.uk/ (search Catalog)
New Dragon Book of Verse Corpus : http://ota.ahds.ac.uk/ (search Catalog).
Northwest Coast Indian mythology Corpus: http://ota.ahds.ac.uk/ (search Catalog).
Online Classics Horror and Phantasy Fiction: http://home.swipnet.se/~w-60478/
SETIS Australian Literary and Historical Texts: http://setis.library.usyd.edu.au/ozlit/
Corpus of Middle English Prose and Verse: http://www.hti.umich.edu/c/cme/
Harry Potter Corpus: http://luwei.2288.org/oechw/hanyu/data/CORPUS/harrypotter/framconc.asp
Towneley Plays Corpus: http://ota.ahds.ac.uk/ (search Catalog)
Web Concordances Site: http://www.dundee.ac.uk/english/wics/wics.htm
York Miracle Play Cycle Corpus: http://ota.ahds.ac.uk/ (search Catalog)
ME Texts Anthology Corpus: http://ota.ahds.ac.uk/ (search Catalog)
7. Web As Corpus
Web As Corpus :http://webascorpus.org/searchwac.htm
Web Corp: http://www.webcorp.org.uk/
WebCONC: http://www.niederlandistik.fu-berlin.de/cgi-bin/web-conc.cgi?sprache=en&art=google
8. Learner Corpora
Chinese Learners of English(中国英语学习者): http://www.clal.org.cn/corpus/EngSearchEngine.aspx
Corpus of Hungarian students' essays:
http://joeandco.blogspot.com/2008/06/writing-subcorpus.html
The Multimedia Adult English Learner Corpus:http://www.labschool.pdx.edu/maelc_access.html
The Uppsala Student English Corpus (USE):
Dowloadable data at http://www.ota.ox.ac.uk/headers/2457.xml
Michigan Corpus of Upper-level Student Papers: http://lw.lsa.umich.edu/eli/eli1/micusp/Contact.htm
IWILL Corpus: http://research.iwillnow.org/project/bncrce/default.htm
Wordneighbours: http://wordneighbors.ust.hk/
PICLE Corpus:http://ifa.amu.edu.pl/~kprzemek/concord2advr/search_adv_new.html
EVA Corpus: http://kh.hd.uib.no/eva/
PolyU Language Bank Concordancer:
http://langbank.engl.polyu.edu.hk/engine.aspx?Submit=Search&lang=1&corpus=16
The Montclair Electronic Language Learners' Database under construction)
http://www.chss.montclair.edu/linguistics/MELD/
Singapore Corpus of Research in Education:http://score.crpp.nie.edu.sg/score/index.htm
Birkbeck Spelling Error Corpus: http://ota.ahds.ac.uk/ (search Catalog)
Open Mind Commonsense Corpus: http://openmind.media.mit.edu/
Corpus for Higher Education:
http://langbank.engl.polyu.edu.hk/engine.aspx?Submit=Search&lang=1&corpus=11
National Taiwan Normal University Corpora:
http://llrc.eng.ntnu.edu.tw/English/search/Default.htm
http://llrc.eng.ntnu.edu.tw/English/search/tag.htm
http://llrc.eng.ntnu.edu.tw/English/search/tag2.htm
http://140.122.83.246/cwb/
http://140.122.83.246/cwb2/
ELISA corpus: http://www.uni-tuebingen.de/elisa/html/elisa_index.html
VLC: http://vlc.polyu.edu.hk/
9. News Corpora
Reuters Corpus: http://about.reuters.com/researchandstandards/corpus/
arpers Magazine 1879-1880 Corpus: http://ota.ahds.ac.uk/ (search Catalog).
Hong Kong South China Morning Post Corpus: http://ota.ahds.ac.uk/ (search Catalog)
New York Newspaper Advertisements and News Items 1777-1779: http://ota.ahds.ac.uk/
VOA Special English Corpus: http://www.manythings.org/voa/sentences.htm
VOA Special English audio and text corpus: http://www.dhytex.com/voanews.html.
American News Stories Corpus: http://ota.ahds.ac.uk/ (search Catalog).
MPQA Opinion Corpus: http://www.cs.pitt.edu/mpqa/databaserelease/