Somewhat related, but Wikipedia actually has a "special page" for searching external links, which I've had a lot of fun with:

https://en.wikipedia.org/wiki/Special:LinkSearch

You can e.g. search for all external links to HN, to pg's website, or to any Twitter user's tweets:

https://en.wikipedia.org/wiki/Special:LinkSearch?target=news...

https://en.wikipedia.org/wiki/Special:LinkSearch?target=paul...

https://en.wikipedia.org/wiki/Special:LinkSearch?target=twit...

You can also use it to get a sense of the adoption rates of new gTLDs:

https://en.wikipedia.org/wiki/Special:LinkSearch?target=*.ng...

https://en.wikipedia.org/wiki/Special:LinkSearch?target=*.de...

https://en.wikipedia.org/wiki/Special:LinkSearch?target=*.pr...

https://en.wikipedia.org/wiki/Special:LinkSearch?target=*.cl...

(I only wish there's a way to optionally filter out links originating from Talk pages, since those sometimes introduce a lot of noise, depending on your purpose)

All the other "special pages" are listed at: https://en.wikipedia.org/wiki/Help:Special_page