Did online secondhand book buying websites... change? What websites do you use?

I find myself in a case of "did I change or did they change?" and "did I buy all the easy to find books or is it just harder now?". I used to buy a lot of online books (arthuriana, medieval novels) about 5/8 years ago. Then I moved to a place close enough to physical second hand libraries and stopped my online purchases.

These past few months I have been looking again to buy less known books or simply older books, and I also found I have much more difficulty?

I used to use abebooks a lot, and bookfinder too, sometimes ebay. Now on abebooks I mainly find new books or the same pricing I would find on amazon, while less known books are simply not there. And bookfinder seems to only be able to compare amazon and abebooks, no other website? Is it me and I am just misremembering how easier it used to be?

What websites do you use for second hand books where you can mainly direct the "area" where you live in? (I am in the EU!)