• http://johnmacfarlane.net/babelmark2 : compare various implementations
• https://code.google.com/p/markdownsharp/ - C# implementation of markdown parser, used on Stack Overflow
• http://stackoverflow.com/questions/888985/what-markdown-c-sharp-library-should-i-use
• http://mistune.readthedocs.org/en/latest/
• http://codegeekz.com/markdown-editors-and-tools/
• https://github.com/mangini/gdocs2md
• http://commonmark.org/
• https://github.com/Knagis/CommonMark.NET - port of stmd
• https://github.com/bevacqua/ultramarked
• https://github.com/jonschlinkert/remarkable
• https://github.com/domchristie/to-markdown - html to markdown in javascript
• https://github.com/leeoniya/reMarked.js - html to markdown in javascript

JavaScript parsers:

• https://github.com/markdown-it/markdown-it - supports plugins, http://www.broculos.net/2015/12/build-your-own-markdown-flavour-with.html
• https://github.com/chjj/marked
• https://github.com/jgm/commonmark.js
• https://github.com/GitbookIO/kramed - fork of marked with decent amount of improvements
• https://github.com/evilstreak/markdown-js, used by discourse https://meta.discourse.org/t/discourse-has-a-new-markdown-parser/9318, https://github.com/discourse/discourse/tree/master/app/assets/javascripts/discourse/dialects - their additions
• http://strapdownjs.com/
• https://github.com/jonschlinkert/remarkable
• https://github.com/brrd/celldown.js - helper for handling markdown tables
• https://casual-effects.com/markdeep/ - BSD, many interesting features
• https://github.com/showdownjs/showdown

On-line editors:

• http://marklighteditor.com/
• https://github.com/benweet/stackedit
• http://prose.io/
• http://marxi.co/ - syncs to evernote
• https://www.beyondpad.com/app#notes/inbox
• http://dillinger.io/
• https://www.gitbook.com/book/kjk/test-book/edit#/edit/master/README.md
• https://fiddle.md/b836w36wh2h8mv3fj23t8r, https://news.ycombinator.com/item?id=9262260
• http://auth0.github.io/mdocs2/#/new
• http://socrates.io/
• http://kjk.roughdraft.io/ - a gist editor/preview
• http://markup.rocks/
• http://jbt.github.io/markdown-editor/
• https://github.com/bevacqua/woofmark
• http://summernote.org/
• https://www.froala.com/wysiwyg-editor/v2.0
• https://github.com/basecamp/trix

Desktop apps:

• http://mouapp.com/
• http://clockworkengine.com/lightpaper-mac/
• http://markdownpad.com/
• http://mike-ward.net/markdownedit/ - WPF, metro-style, open-source
• http://realmacsoftware.com/typed
• https://github.com/leeoniya/reMarked.js, http://leeoniya.github.io/reMarked.js/
• https://github.com/brrd/Abricotine - electron, gpl