Good Vibes Preserver от Cofeiini

Good Vibes Preserver uses crowdsourced reporting and voting system to hide content that is considered unpleasant, which can be customized in the extension settings.

The extension adds a new context menu item for reporting or revealing content.
The options page (accessible through the extension menu) has a help section showing the basic flow of reporting and previewing/revealing.

Currently only images can be reported and voted on, but other media formats are planned to be supported.

Source code: https://github.com/Cofeiini/GoodVibesPreserver