You have several options to unblock a YouTube channel; 1- Undo Blocking Instantly: When you click on the block button and block a channel, you will notice an unblock button appear for a few seconds.  You can unblock a channel instantly by click that button. 2- Using Google: The Google Activity page is another method to unblock YouTube channels. Reach the page and go for the other activity option. You will find ‘’YouTube not interested feedback’’ among the other options. You can unblock channels from there. 3- The Flag Button: Enter the blocked channel’s YouTube page. From the ‘’About’’ section, you will find a flag icon(button). Once you click the icon, you can see the unblock option appear in front of you.