Recommended online question banks or practice papers for revision of Mathematics Optional subject include:

1. EduRev: EduRev is a platform that offers a comprehensive collection of question banks and practice papers for the Mathematics Optional subject. It provides a user-friendly interface and a wide range of questions from various topics, allowing students to practice and revise effectively.

2. Topic-wise question banks: Many websites provide topic-wise question banks that cover all the important concepts and topics of the Mathematics Optional subject. These question banks are designed to help students focus on specific areas of the syllabus and strengthen their understanding and problem-solving skills.

3. Previous year question papers: Solving previous year question papers is an essential part of exam preparation. It helps students familiarize themselves with the exam pattern, understand the types of questions asked, and assess their preparation level. Many online platforms offer access to a wide range of previous year question papers for the Mathematics Optional subject.

4. Mock tests and sample papers: Mock tests and sample papers are designed to simulate the actual exam environment and help students assess their performance. They provide an opportunity to practice time management, improve speed and accuracy, and identify areas that require further revision. Online platforms often offer a variety of mock tests and sample papers for the Mathematics Optional subject.

5. Online forums and discussion groups: Engaging in online forums and discussion groups dedicated to the Mathematics Optional subject can be highly beneficial. Students can interact with fellow aspirants, share knowledge, discuss challenging concepts, and gain insights from experienced mentors. These platforms often provide access to additional resources, study materials, and practice questions.

In conclusion, EduRev is a highly recommended online platform that offers a comprehensive collection of question banks, practice papers, and other resources for the revision of the Mathematics Optional subject. It provides a user-friendly interface, topic-wise question banks, previous year question papers, mock tests, and access to online forums and discussion groups. Utilizing these resources effectively can significantly enhance students' preparation and performance in the Mathematics Optional subject.