Hello Aspirant,

I don't know about many but one I came across is amazing, so it is called as plancess and they have above 339 lectures available on their YouTube channel which includes mathematics founded by IITians,plancess Edu solutions Pvt.Ltd.is one of India's leading companies for entrance test preparation.plancess products are designed and developed in consultation with experts and top rankers in the respective entrance exam.
No channel is best for chemistry in YouTube only self study and NCERT is enough...but if you are studying then new era coaching or atp academy or dushyant Kumar can be referred...

Thank you!!!