Are there any adventures available for GURPS Supers?
Yes. GURPS Supers Adventures is a book of four adventures. Other GURPS Supers adventure supplements exist: “Deathwish,” by Loyd Blankenship, is a 32-page adventure book, as is “School of Hard Knocks,” by Aaron Allston. Note that these were written for first-edition Supers rules, so some work is needed to use them with Supers, 2nd Edition. “Aces Abroad,” by Kevin Andrew Murphy is a GURPS Wild Cards adventure supplement. There is also a 5-page Supers mini-adventure in IST Kingston, published by Modern Myth, set in Jamaica of the IST world.