I personally think that all the materials within the Straighterline course and the exams, midterms will be great reviews for most courses. If you happen to be taking courses with an open book exam, nothing more is required.
For the proctored final, they will ask you if you would like to use a sheet of personal notes, I keep saying no as the resources from the text is sufficient, if you want that sheet for extra help, prepare one...
If you are wanting to find out what courses are easiest or best, I would recommend taking courses with 4-6 exams, midterm and open book final that is 20-30%, or any closed book exam with a final grade weighted worth less than 20%. The next best are courses with a closed book exam worth 30% or less, this way, you virtually pass the class when you take the final.
Just look for their grading criteria in their course details/outline or syllabus, and this link for open book exams.
Online Exam Proctoring Details by Course | StraighterLine
View the bottom of this page for etextbooks or text that SL uses, if you have the right edition for open book exams, you are good to go.
Shop eTextbooks & Textbooks for Online Courses | StraighterLine
An example of how well I did and am doing on both open book and closed book courses.
Medical Terminology: Final Grade 99%, I had one exam at 98% and open book proctored final at 98%, done in 3 days. Essentially, I did all the exams in two and a half days and final the third day, as I booked it immediately when I took the course.
Microbiology: I bombed the first exam and had 85% the second exam, after redoing the initial exam and completing midterm and additional exams, I am at 95% with the CLOSED book exam tomorrow. So, by calculation, I have 95% of 80 which is 76%. Essentially, I can get 0% tomorrow and have 76% final grade, but for personal reasons, I shoot for 90% or higher in every course.