5 links
Phrase Finder
phrases.org.uk
Enter a single word and it will return a list of phrases and sayings that are related to the word in some way.
Roget's II - The New Thesaurus
bartleby.com
Contains 35,000 synonyms, succinct word definitions and a hyperlinked category index.
Roget's International Thesaurus of English Words and Phrases
bartleby.com
85,000 hyperlinked cross-references, plus proverbs and quotations from classic and modern authors.