BBC BitesizeBBC Education have produced a whole host of materials for KS2. Follow the KS2 link and then select either Maths or English. Each area usually has an information section for reading, plus an activity and then quiz which is marked online. Some aspects require a subscription.
IXL Maths and EnglishIXL have separate pages of skills linked to individual Year group. The Y6 page has links to practise both English and Maths skills. Pages are then split into skills of which has a practise question for the children to think about.
Education Quizzes A site with both Maths and English based quizzes which are marked as you go along
TopamarksA range of English and Maths games, including our all time favourite of ... Hit the Button