The feature allows users on the Facebook platform to block those they don’t want to associate with anymore on Facebook.
How do I see my blocked list? How to view your blocked list on messenger?
Also, users are allowed to unblock those they blocked on facebook. Are you trying to find the people you blocked on Facebook or messenger, probably to unblock them?
Then don’t worry, as, in this guide, I will show you how to view your Facebook or messenger block list and also unblock them.

How To Locate Your Blocked List On Facebook 
1. Click 🔻in the top right of any Facebook page and select Settings.
2. Go to the left side of Facebook and click Blocking.
3. In the Block Users section you should see a list of people you’ve blocked.
4. Click Unblock next to the name of anyone you want to unblock.
5. Click Unblock next to the name of the person you want to unblock.
6. Click Confirm to finish unblocking the person.

Note: If you unblock someone, you won’t be able to block them again for a few days. How to unblock someone in Messenger

If you’ve blocked messages from someone, you can unblock them later.

To unblock someone on Messenger:

On iPhone and iPad devices: 
1. From Chats, tap your profile picture in the top left corner.
2. Tap People and then tap Blocked.
3. Tap the name of the person you want to unblock.
4. Tap next to Block Messages to unblock them.

On Android Devices: 
1. From Chats, tap your profile picture in the top left corner.
2. Scroll down and tap People.
3. Tap Blocked people.
4. Tap Unblock next to the name of the person you want to unblock.
5. Tap Unblock on Messenger.