AFAIk, there are no other resources that are better than what College Board offers free. There are companies that will give you some sample tests when you sign up with them, but they are using their own material, which is not like a real test in my opinion.
Have you tried the question bank? You can filter questions based on type and difficulty level. There are three versions of the PSAT, plus the linear tests. You can probably find some site that still has the original linear tests 1, 2 and 3. Be warned that many of CB’s tests, including question bank, contain recycled material though. The good news is that even when kids say they have previously seen that question, they are unlikely to remember the answer.
Students don’t need to race through the practice material. In my work, I pace it. We use one of the PSATs as our practice together, we use question bank, we use linear tests. They do the digital tests as homework. When they run out of material, we start with Test 4 again, as it’s usually at least a couple of months since they have seen it. They don’t remember the answers, and it’s interesting to see if they struggle with the same questions.