Order Mail to Manufacturer Magento Extension
This extension can be used to send an email alert to Manufacturer to update them about the order of their item. And So they can process their orders.
Product Attachments Magento2 Extension
This extension allows admin to add different attachment files to the site. And admin can assign attachment to different products and/or to customers.
Custom Options Csv Pricing Magento Extension
This extension basically used to save custom options pricing using csv. It will work when you have 2 custom options.