I start at the dr.loudness-war web site:
This is a database of all types of media that gives dynamic range measurements by track, album average, low and high.
It is my opinion that if the dynamic range is compressed too much then it doesn’t much matter what’s on the CD or how well it was engineered otherwise. Some may disagree but I think you have to start with dynamic range.
Once you find the best CD on that site in terms of dynamic range then you can go to eBay (or where ever else) and search. You use catalog numbers, dates or bar code numbers to identify the specific CD. I do not recommend Amazon because the CD identifying info is rarely included.
I’ve had excellent success doing this. And CDs on eBay are cheap.
Also, almost all CDs produced lately have awful dynamic range.
Finally, beware of "remastered" CDs. I have found that they are usually worse than the originals and almost always more compressed.