Use Twitter's Open Source SVG emoji to build your own emoji/abominations.
EmojiBuilder is currently very much in beta, check out the roadmap project for all the function that should be implemented shortly. If you think something is missing, put in an issue above!
If you have a stellar idea to implement one of the above functions, go ahead and put in a pull request or issue with your suggestion! I dont really adhere to any particular standard, but try to follow best JS practices and some degree of commenting in your code.