The Tracker and Ad Blocker comes with a large selection of sources that can be enabled to block unwanted content on web pages. You can enable them in the browser’s Privacy and Security settings. In addition to the default sources, you can add your own custom source lists. To do that:

1. Go to Settings > Privacy and Security > Tracker and Ad Blocker > Manage Sources.
2. Click on Add List below Tracker Blocking Sources or Ad Blocking Sources lists.
3. Locate the sources .txt file in your File Manager/Finder.
4. Click Import.

The newly added list will be automatically enabled.

To find additional sources, you can start by checking this Forum thread, where Vivaldi Community members have shared the blocking sources they use.