Is there any moodle plugin for resource ratings?
I've searched https://moodle.org/plugins/ and couldn't find any.
I'm not really familiar with moodle, so it would be helpful if You tell me in which category to search.
No, you can rate courses and you can rate forum posts but there are no existing out-of-the-box plugins for rating individual resources.
For future reference, you should tag your question with what version of Moodle you're using in order to enable other StackOverflow users to give you accurate advice.