I'd probably recommend you get them off ebay/vce forums and stuff because a lot of people buy it, barely use it and end up re-selling.
English - I used insight encountering conflict study guide. They had a lot of good ideas/notes and exercises to try and get you to make your own intrepretations/ideas but I couldn't be bothered doing it. Used NEAP one also and it probably isn't worth it to get both. Basically, you can use this to get ideas/sample essays but in the end, the most effective thing will be the exercises that try and get you to broaden your intreptation,understanding and analysis of the text/context.
Specialist - Probably just textbook and exams would be sufficient. If you have the time ( finish the course early), you could probably go through A+ notes, exam busters, leading edge exercises, A+ exams but your first priority should just be the textbook, checkpoints ( if you want) and exams.
Methods - Found that the textbook and checkpoints and exams was sufficient. A+ notes wasn't too bad.
Basically for the maths subjects, i'd just say textbook to understand + do questions and then checkpoints + exams to improve. The other stuff may/may not help. EG: I did the A+ exam books and I found that it was practically useless.
I dunno how much time you're gonna spend on year 12 but if you managed to finish the course early, then you would probably have time to do all the extra exam revision books.