Works quoting the UK National Anthem.

[Leea25]

I'm pretty sure one of Debussy's preludes quotes it too... Hommage a Pickwick perhaps?

[saxtromba]

The tune known in England as "God Save the [gender of reigning monarch]' is also a major patriotic tune in something like twenty different countries, including Brazil and Germany (and some people have already mentioned examples from the United States), so I'll bet there are plenty of pieces which quote the tune without the composer having thought of England at all.

[JimL]

Weber and Raff's Jubilee Overtures both quote it in entirely different contexts than British.

[TerraEpon]

I'm pretty sure one of Debussy's preludes quotes it too... Hommage a Pickwick perhaps?

Hommage a S. Pickwick Esq. P.P.M.P.C.
To be exact

Gottschalk also wrote a piece based on the melody, and I believe (but am not sure) he quoted it elsewhere.

[chill319]

The tune is prominent, and nicely worked out, in Clementi's Symphony 3.