Any links to score examples of classical, metal, or other music would be great.
It depends on how local your viewpoint is, but here are some fun ideas that composers have used:
It's common for a Neapolitan to move through an applied chord to the dominant before moving to the dominant proper. Thus a Neapolitan sixth, with scale-degree 4 in the bass, can move through (for instance) a viio7/V (#4 in the bass) up to V (5 in the bass), creating a nice chromatic line in the lowest voice. (You can match this with the descending chromatic line in the soprano of b2--1--7 if you want!)
ttw references Chopin Op. 48, No. 1. This is actually my favorite use of the Neapolitan, but it's actually an applied chord to the Neapolitan. In this video, you can watch the score as it happens. (The measure in question is the second measure of this screen, but I recommend listening to the whole thing to get the real effect!) Chopin sets up what you expect to be the final cadence of the piece with a big dominant chord, built on G (scale-degree 5) in C minor. But instead of resolving this to tonic, Chopin resolves this to an A-flat dominant seventh chord in third inversion (?!), with G-flat (scale-degree b5?!) in the bass. As it turns out, this is actually just a V42 of the Neapolitan, and since the Neapolitan is so often in first inversion, this G-flat just slides down a half step to the F of that Neapolitan chord. At this point he then moves to the dominant and tries the cadence again.
Similarly, composers will just hang out on the Neapolitan sometimes, embellishing it with its own dominant. Let's say we're in E minor; the Neapolitan sixth is an F-major chord with A in the bass. A composer could just alternate between this chord and the V42 of F major (C7 with B-flat in the bass) to hang out in Neapolitan land for a bit before returning back to F major and doing whatever s/he ultimately wanted to do. A number of pieces do this, but my memory is failing me right now...
Neapolitan chords can also be used as pivot chords (also called "common" chords) in modulations. For instance, in the above Chopin example, the Neapolitan was a D-flat major chord. Since D-flat major chords exist in multiple keys, Chopin could have gone to that D-flat major chord in C minor but then left it in another key. As one possibility, we know that D-flat major appears in A-flat major as the IV chord. So, Chopin could have gone from his D-flat major chord in C minor and treated it as IV in A-flat, moving straight to an E-flat dominant (V7) and resolving to A-flat (I).
Or, you can go the other way. Hang out in A-flat, and when you get to a IV chord, resolve it as if it was the Neapolitan in C minor!
And you can also use Neapolitan chords in sequences. Start on a tonic chord. Then let's just have a string of V7--I progressions, where each I is a half step higher than the I two chords earlier. So one progression could be: C, Ab7, Db (the Neapolitan), A7, D, Bb7, Eb, etc. Though here it's a little silly to call that Db the Neapolitan, since it doesn't really function that way at all.
I'm sure there are other fun things to do with Neapolitans, but these are all that came to mind at the moment!