Writefull Thesaurus - A Google Docs add-on that uses AI to give you synonyms
Urban Dictionary - Urban Dictionary is a Web-based dictionary of slang words and phrases.
Dictionary Anywhere - Dictionary Anywhere is an open-source and easy-to-use browser extension for Mozilla Firefox and Google Chrome that allows you to check definitions easily while browsing the web.
SlangSite.com - SlangSite.
Silicon Valley Dictionary - Urban dictionary meets Silicon Valley
Reverse Dictionary - Describe a concept and get back a list of words