You can load new products (with 0 quantity) by the import mechanism.

Open the Product menu (left pane), then click on import.

The data (names of products) to import need to be in a text file (extension csv) preparedby a spreadsheet app (excel or libreoffice); the only field needed is the "Name" (one column).

The parameters of the csv file are UTF-8, and a ", " as separator. Make sure the names of the products do not include a ","

I recommend you to make a test with a csv file containing one or two products to import; if it works correctly them import all your other new products.

• in addition to the above

see also https://www.odoo.com/forum/help-1/question/how-to-import-quantity-on-hand-59983

You need to first create an inventory item; then export it to a csv file.

Second: export the list of products with zero qty.

Add to this product.product file the columns of the inventory file (the first one created); This should form a final file where you will change the quantities per products. Save it and import on the product screen.