For science Id recommend Cognito because they have quizzes, lessons with videos as explanation, practice exam questions (not from past papers either cos you’ll need them for the GCSE season so that’s great), flashcards etc so if you don’t already id advise using that. Bitesize is really good for in depth explanations of topics. Also CGP books are great if you dont have them already and prefer paper resources. If you struggle with calculation questions then use Isaac physics to practice them 🙂
For maths, the more practice you can get the better so id suggest making use of the Corbett maths 5-a-day. Cognito as does maths videos, but I didn’t use them personally- i do recommend them but i dont have experience of them! I used Corbett maths videos and also gcse maths tutor- make sure to check them out for topics you’re unsure on.
Hope that helps!