Chumlee, in my opinion the revision for boards is best done through the NCERT and the previous year papers, preferably by ARIHANT as they help not only in improvement of concepts but also give you an idea of the type of questions asked. By NCERT, I also mean the prepartion of the Optional or Miscellaneous exercises as quite a few questions are framed from the concepts of these exercises. Now, regarding the online classes, I believe you can take help from Aman Dhattarwal's channel as he concentrates on the exam pattern accurately and his notes are absolutely to the point and sufficient with respect to the need of the exams. In addition to it, he shares a few strategies too which mayhelp you in your own preparation. But, I would advise you to first finish off the NCERT atleast twice for your revision as the paper is more or less prepared in tandem with its' text.