The site is called Problem Attic, and it is exactly what it sounds like. It's an "attic" full of old test questions. The test questions are taken from banks of standardized tests for a bunch of different states. I think the site started as a repository for New York Regents exams, but it's expanded to many other states, too.
Sadly, the test questions for Oklahoma are behind a paywall. Though, it's not the end of the world because I know how to access the released test items from the state of Oklahoma's website. Most of the site's resources are free for the taking. I think you should definitely take a little time to explore!
If standardized test prep questions aren't up your alley, there are also math competition questions that would provide your students with quite a challenge!
Plus, there are more than just math questions, too! The questions are pre-sorted by topic, so it makes it easy to find the type of question you are looking for. Since I don't use textbooks, I don't have a test bank access when writing assessments.
Since moving to SBG, I've used this less and less as I write my own questions more and more. But, as a beginning teacher, this site saved my life numerous times. Writing good quality multiple choice questions is time consuming. It's so nice to be able to just pull up a list of questions and choose the ones that fit what you are looking for.
The site gives you tons of options for formatting your document to look nice and pretty.
Here's what one of my test reviews ended up looking like: