I had forgotten about JMAP until I posted the Saxon book. http://www.jmap.org
Jefferson math Project has a ton of resources for math from various different publishers. The best thing about it is the FREE worksheet generator. You can make your own or choose from a catalog of thousands of problems. When I couldn’t get an answer key/test book for an old Saxon book I used it to make tests. Saxon tests on lesson 10 for lessons 1-5. You are always 5 lessons behind when testing. Anything coming before the previous 5 lessons can show up on a test.
The other thing we used it for was Khan Academy. It has past NY Regent exams with answers. I used those as a final to make sure my son knew the material before I posted a grade in his transcripts. The exam counted as 1/5 of his final grade. If you want the old regents you’ll have to look through the Regents Archives. In Regents Resources you can get tests for other subjects besides math.