There are several online courses and webinars available that provide in-depth knowledge on various subjects related to UPSC. These courses are designed to help aspirants prepare for the UPSC examination and gain a thorough understanding of the subjects included in the syllabus. Below are some of the popular online courses and webinars that can be helpful:

1. EduRev UPSC Course:
- This online course offered by EduRev is specifically designed for UPSC aspirants.
- It covers all the subjects included in the UPSC syllabus, including history, geography, polity, economics, science and technology, etc.
- The course includes video lectures, study materials, practice quizzes, and mock tests to help aspirants prepare effectively.
- It is a comprehensive course that provides in-depth knowledge and guidance for all stages of the UPSC examination.

2. Unacademy UPSC Courses:
- Unacademy offers a wide range of courses for UPSC preparation.
- These courses are taught by experienced educators and cover various subjects in detail.
- The courses include live classes, video lectures, study materials, and doubt-solving sessions.
- Aspirants can choose courses based on their requirements and preferences.

3. BYJU'S UPSC Courses:
- BYJU'S offers comprehensive online courses for UPSC preparation.
- The courses include video lectures by experienced faculty, study materials, and practice questions.
- They provide in-depth coverage of the UPSC syllabus and help aspirants understand the concepts effectively.

4. InsightsIAS Webinars:
- InsightsIAS conducts regular webinars on various topics related to UPSC preparation.
- These webinars are conducted by experts and cover subjects like current affairs, essay writing, answer writing, etc.
- Aspirants can attend these webinars to gain insights and enhance their knowledge on specific subjects.

These are just a few examples of the online courses and webinars available for UPSC preparation. It is important to thoroughly research and choose a course or webinar that aligns with your requirements and learning style.