A Level Revision guides (maths, bio, chem)

I usually go for the CGP books because they seem to be the best. I used one for further maths and chemistry during my A-levels and found them very useful (especially during quarantine) because they explained everything in more detail than textbooks sometimes do.

If you know you need to do practice questions to help you consolidate your understanding, I would suggest buying the workbooks (CGP again) as many people have recommended them to me. Although, if you're more likely to use physics & maths tutor for maths, perhaps don't bother with the workbook.

I would suggest buying the revision guides for both years, unless you know which subject you might finish at AS level.

In terms of online resources, I used Chemguide a lot for chemistry, as an alternative to textbooks but be aware that it sometimes goes a bit beyond A-level (though it usually tells you which parts aren't needed). I also sometimes used Seneca for chemistry as a refresher for some topics, but I have found that some knowledge is missing.

I hope that helps!