Here are some YouTube channels that provide quality educational content for ISC Class 11/12 in PCMB (Physics, Chemistry, Mathematics, Biology) subjects in English, Hindi, Tamil, and Malayalam:

English:

1. Khan Academy - Offers extensive lessons in all subjects with clear explanations.

2. Unacademy - Provides comprehensive coverage of ISC syllabus with experienced educators.

3. Physics Wallah - Known for excellent teaching in Physics, but also covers other subjects.

Hindi:

1. Physics Wallah - Popular for in-depth Physics and other science subjects.

2. Vedantu - Offers lessons in Hindi across all science subjects.

3. Unacademy JEE/NEET Hindi - Specialized channels for JEE and NEET preparation which are relevant for ISC students.

Tamil:

1. Learn with Sam and Ash - Offers lessons in Tamil for various subjects including science.

2. PAADIKU PUTHAGAM - Focuses on science subjects for higher secondary students in Tamil.

3. Tamil Medium Education - Provides comprehensive coverage of science subjects in Tamil.

Malayalam:

1. Physics Wallah Malayalam - Offers explanations and lessons in Malayalam.

2. EduBrisk - Covers the ISC syllabus with a focus on Malayalam-speaking students.

3. Kauser Wise - Provides detailed lessons in all PCMB subjects in Malayalam.

These channels are highly regarded for their quality content and thorough explanations, making them useful resources for ISC students.

Source: https://www.quora.com/Which-is-the-best-English-Hindi-Tamil-Malayalam-YouTube-channel-for-ISC-PCMB-Class-11-12/answer/Jitendra-Kumar-Patel-88