• VENDANTU JEE
  
• eSARAL
  
• MOHIT TYAGI
  
• UNACADEMY JEE
  
• AMAN DHATTARWAL
  
• NCERT KAKSHA
  
• NEHA AGARWAL
  
• VEDANTU MATH
  

Nowadays there are numerous JEE channels in youtube. But always remmember that all the channels are not credible and there are many channels which misguide students towards false techniques and short cuts which doesn't help the student in anyways for the examination but it gives false hope to the students and as a result the student unknowingly make there preparation weak. So be aware about this.

Now for Mathematics for JEE MAINS and Advanced there is the legend there providing videos for the students at free of cost. The channel name is Mohit Tyagi. Mohit Tyagi is one of the well know authors for JEE ADVANCED and he also keep this platform up to help and guide students. So nothing can be best than the legend sitting there waiting to help you. So you can obviously follow his channel. Apart from this you can follow Vedantu, Unacademy etc but this are mixed classes and its intended to sale courses. So if you want to get study from youtube follow Mohit Tyagi and you will definitely feel how good is he.

I hope this answer helps. All the very best for your future endeavors!