Here I will show you where you can find those extensions.
Opera[addons.opera.com]
Chrome[chrome.google.com]
Firefox[chrome.google.com]

This Tutorial is only about the Chrome Extension.

In the second step you will blacklist every gambling site!
To do that, you have to enter the site urls as shown in the picture.

To block the extensions menu, you will have to click on the off button.
This action will prevent you from blocking the extension.

In this step I will show you how to prevent yourself from making the sites accessable.
In order to do so, you have to get a strong password first.
I prefer using this SitePasswordgenerator[passwordsgenerator.net]
After you have generated that password, create a new notepad and paste the Password in it.
After that you have to enable password protection in simple blocker, and paste your Password into the two rows. And click "Save".

But if you still do, do it here I cry[how.icryeverytime.com]

Do it, and stop other people loosing skins, like I did.
RiP