Try the search box at the very end of the front page. The Algolia search can sort the results by score but will contain mentions of the page in textual submissions (but not comments, at least by default). You can improve the results by making it particularly specific, e.g. by searching for "https://www.gwern.net". Include the quotation marks and note that you would have to do this for both https/http to get all submissions.
This might be halfway to what you want to achieve. There are some filters you can use. Check them out here: https://hn.algolia.com/help