@g0st Pushed an update so that the topic cards use the topic thumbnail if available, and added a few extra options in the widget config.
Feel free to open any other feature requests in the github issues.
What have you tried? This is possible to do via a plugin.
This can also be done by using
Mark as unread for all option in the topic tools dropdown, it will mark the topic unread for everyone without making a new reply to it.