What is the best way in Commerce 2.x to allow the shopper to check boxes to add optional accessories to a product before he adds the product to the cart. In addition, the product price should be updated.
Sounds like this module would do it in D7: Commerce Product Add-on.
This question asks the same question, but it's tagged with 7. Can a VBO form be integrated with the Commerce Add-to-Cart form to allow adding optional add-on products with checkboxes?