I will build a custom Wordpress plugin for you to achieve custom functionality that you can't find in existing plugins.
This could be:
a form to access custom database tables.
HTML/CSS/JS code to display data coming from outside Wordpress (JSON, files, database)
a custom filter to process specific Wordpress posts.
add new admin submenus.
social media integration.
e-commerce integration.
API Service.
A sub extension/add-on to an already existing plugin.