I'm guessing you're referring to the Spanish Fantasy for the second one?
I'd also like to add the Transcriptions of Beethoven's Symphonies, S. 137 and S. 140 Etudes, and the S. 700a/ii (I would argue that it's an equally challenging, if not more challenging "La Campanella" than La Clochette is).GGC and Feux Follets are kind of an in-between level, along with a few other things e.g S. 140 La Campanella.
I personally wouldn't put the Beethoven transcriptions and etudes at the same category as La Clochette or the Spanish Fantasy as the latter are the ones Liszt did for quick money and to prove that he was without competition...
Personally I would also say Feux Follets is at a whole different level than GGC. The spirit of a "virtuoso showpiece" typically meant some crazy arrangement over a popular theme which dominated the salons of the early 19th century. Nearly every opera transcription by a romantic composer for the piano would qualify under this label.
The S.700 is crazy, too - though I have a special fascination with the "Clochette" as it is a particularly absurd work even for Lisztian standards, both technically and harmonically. It's the direct result of him hearing Paganini play live for the first time and probably what he worked towards while doing his "exercises for four to five hours a day" as he had written.
Another work that I would personally recommend, which is probably easier than Liszt's transcriptions, is Thalberg's "Don Pasquale" fantasy - Earl Wild's recording is a must-listen. The arrangement is wild - as if four hands were playing simultaneously, especially near the end.