Grammar

Not sure if what you are looking for, but KISS grammar has free online resources. You could print off specific worksheets for specific topics, and they also have answer keys. The sentence  selections tend to come from older books.

Their web page can be a bit awkward to navigate, trying to figure out which level, but I have used some of the worksheets successfully with my kids to help review some concepts, especially before testing (required in our state) just to give a refresh and a bit of confidence boost a couple times a week leading up to the test. I discovered it really bothered my daughter when the test covered too many things she had not learned yet (even though I was fine with waiting), and selecting some of these worksheets helped a lot to review and present a few new concepts with out a full curriculum.