If you are not yet ready to create a display campaign, but would like to research available placements or check if specific websites are part of Google's Display network, you can use Google's Placement Tool. You can also use this tool if you have already created a display campaign that you'd like to build on and expand with additional placements.
Put together a list of websites you'd like to show ads on. Also, prepare keywords and product categories to search for additional available placements.
To find placements, perform the following steps: