How to display all products for selection in bundle items tab in admin side?
What's special about the product that you're looking for. It may be that you're looking to include a configurable/composite product in your bundle which isn't possible. You can only include simple products in a bundle in Magento out of the box. To create the illusion of a bundle product, you'll need to replicate all of the configurable options within the bundle product by including all of the possible simple products that you may need.