What Ahmad said, in OBIEE you can't add a custom visualization to the list of available views.

In Data Visualization Desktop (and by extension Data Visualization or the old name Visual Analyzer) there is a concept of "plugins" which are visualizations based on javascript libraries. But there is a SDK mode in DVD to develop and test these plugins, something not existing for OBIEE.

But you can definitely make something similar in an OBIEE analysis, you build and package your visualizations into javascript using RequireJS for example to load all the required files at once and then provide the 2-3 lines of JS code required to display it and provide that to your user as "documentation" (or copy/paste templates).

Sure it still require to do things by hand, but it will be "copy/paste these 4-5 rows of code and add a narrative view passing "these" arguments, done!".