The QUESTION
It seems that Google doesn’t publish any list of sites that are member of their network, in their placement search their is never any premium placement like for example the well known newspapers, medias or websites that are reference in their category.
How do you proceed to target them ? Are you entering the maximum urls and hope they will be member of the GDN or is their a more convenient way to detect them ?
The ANSWER
Unfortunately, there is no list available with all the websites that belong to GDN (Google display network).
You need to find websites and YouTube Channels and YouTube videos that are 100% relevant to your business.
If you don’t know where to start, choosing placements is not the right option.
I would start with other targeting methods like Affinity or In-Market Audience or a Custom Audience based on the keywords you would like to target.
I would create a conversion and then let the campaign run for a while.
After 1-3 months, I would check the conversions and the website these come from.
In that list, you may find suitable placements that get you a lot of conversions.
Now you can create a separate campaign and target only these sites.