Welcome to the Pi-Hole community!
There is no master list that I know of. Sometimes a Google search will return a useful result if you search for that domain, but this is hit/miss. The Reddit r/pihole forum frequently gets requests for "what is causing these domain requests."
The first step is to determine which client is creating the request. Then it's a process of looking at what software is running on the client, and look at the patterns in the request (you can do this by tailing the pihole.log - Admin GUI > tools). There is also the element of time - after a while you will see repeated requests and patterns that help you narrow it down.
Here is a good FAQ on how to find where an ad is coming from. You can use these techniques in reverse as well to figure out what is requesting what. DNSThingy Chrome extension is a good tool.