Even I have been using the online platform since 2018 so I have seen the upbringing of many new platforms in recent years.
Platform
2.) @Vedantu
3.) @Gradeup
4.) @CarrierPoint
5.) @SSBCrack
6.) @Coursera
7.) @Youtube
8.) @IITToppers
9.) @ApniKaksha
10.)@PhysicsWala
11.)@Toppers
I have a used them much and here is the real reason for this post to help you, students, out there to select the best one for the preparation, well you cant go through all of them
For Physics- @NamoKaul(Mechanics)
@PhysicsWala(12th class)
For Chemistry- @VT Sir(Inorganic)
@ParasThakur(organic)
@Pahul Sir(physical)
For Maths-@Neha Aggarwall(Vedantu)
@Sameer (Unacademy)
@Coursera
for NDA-@gradeup
@SSBCrack
@Nehru nfa
@Sure Shot Academy