How to learn flutter for free in 2020

As flutter grows in popularity it also becomes more confusing on how/where to start learning flutter because more courses,blogs and videos are made for it,even youtube gets littered with many flutter tutorials, so based on my 4 years of experience in flutter I will be enlisting some useful youtube channels

1.Smartherd channel on youtube:
IMHO this the first place every noob flutter developer should go to, he first of all walked through Dart language which flutter uses , before doing a little project on a TODO app
https://www.youtube.com/user/smartherd

2.MtechViral channel on youtube:
For me this is the most active flutter channel on youtube , He releases videos almost every week,Infact this guy is awesome and he has some good content in his channel and he has been helping the flutter community since day one,make sure you check his videos out.He also has an active group on facebook named "lets flutter with dart" that has been helping a lot of flutter developers
https://www.youtube.com/channel/UCFTM1FGjZSkoSPDZgtbp7hA

3.Techie Blossom channel:
In fact apart from being cross platform flutter is best known for its beautiful UI and easy to implement animation, this guy always tries to bring out what flutter is best known for, have learnt a lot of UI designs and animations in flutter from him, make sure you check this channel out i bet you will love it.
https://www.youtube.com/channel/UC3wqIkiaOUpO6EjJoCwH6_Q

4.Tensor programming :
This channel contains video from an experienced polyglot software engineer that mostly deals with the logic part of flutter he doesnt focus that much on UI, I must confess i learnt most what I know today as a flutter developer from him, i will encourage every flutter developer both noob and experienced to subscribe to his youtube channel.
https://www.youtube.com/channel/UCYqCZOwHbnPwyjawKfE21wg

5.Filled Stack channel:
Since state management is one of the most debated topic in flutter, this channel will teach you how to architect your flutter application using MVVM architecture, Provider state managements and getit for dependency injection, He's a great guy, so many people have been using his architectural style in flutter due to its simplicity and robustness
https://www.youtube.com/channel/UC2d0BYlqQCdF9lJfydl_02Q

6.Reso coder channel:
To be honest this is the best channel for flutter on youtube though it maybe subjective, as he always says in his videos "his mission his to make his viewers in demand flutter developers",hes not just saying that, he has a 7 hours course on TDD and currently releasing a Domain driven design course in flutter all for free, This channel is for every flutter developer there are lot of things to learn there.
https://www.youtube.com/channel/UCSIvrn68cUk8CS8MbtBmBkA

7.Flutter channel:
This is the official flutter channel on youtube,It is a must subscribe for every flutter developer , Most flutter announcements and updates are first published there and I enjoy the widget of the week series and its " flutter boring show" series.
https://www.youtube.com/channel/UCwXdFgeE9KYzlDdR7TG9cMw