Two high-profile examples come to mind, both in the bridges.

1. Britney Spears - "...Baby One More Time"

To my ears, the bridge is something of a thematic transformation, where instead of the typical introduction of a new melodic idea out of thin air, it transforms the ideas we've already heard into something new.

So the bridge starts out with the opening phrase from the verse ("Oh baby, baby, how was I supposed to know"), except now the texture is thinned way out, more like an A/C ballad and less like the R&B* midtempo song it was for the first two verses. Also, while the verse closes the phrase on the expected C minor chord (the song is in C Minor), the iteration in the bridge ends the first phrase on an Ab Major chord, quite open-ended (or "deceptive"). Then this phrase is repeated, except the harmonies kind of "brighten," and the melody is allowed to vary, leading to the next part...

Next, the chorus melody is transformed into something new. He (= Max Martin) built the original chorus from straight four-note fragments ("My-lone-li-ness," "is-kill-ing-me," "I-must-con-fess," "I-still-be-lieve"). The fragments emphasize strong beats but fit together in a way that's somewhat syncopated, alternating between starting on the & of 1 and the & of 4. In the bridge, we use these four-note fragments to build our new idea, except they recur more regularly, always starting on 3. Well, with the way the lyrics have been rearranged, we tend to have a fifth note that sneaks in before on the & of 2 (kind of the same idea as an upbeat). Even though these fragments occur more regularly, beginning on 3 makes the emphasis of the last note land on the & of 4, adding a new flare of syncopation. So the fragments in the bridge become "I-must-con-fess," "(that)-my-lone-li-ness," "(is)-kill-ing-me-now." The notes on these fragments are exactly those on "give me a sign" (Eb-F-G-G) from the original chorus, but now we're using them as a motif from which our transformed bridge melody will blossom from on "don't you know I still believe." Then we hear the fragments a couple more times, transitioning into the final chorus.

I think it's neat that this song is a prime example of, I don't know, maximalist Y2K teen pop, with hooks galore. Yet the bridge is incredibly economical, from a thematic perspective. I dislike that "poptimism" has turned into a synonym for blind celebrity/major label worship, when it should be a simple acknowledgement that pop is just as capable of brilliant songcraft and artistry as any other genre.

*I fully believe that if a black artist had performed this instead, it would be considered an R&B classic and not a pop classic. And if she sang "No Scrubs," it would be considered a pop classic and not an R&B classic. The way we perceive genre is still segregated unfortunately. But yeah, "...Baby One More Time" is R&B through and through.

2. Shanice - I Love Your Smile

Now this was a big hit when it came out, but it's likely that large swaths of this subreddit haven't heard it, since it perhaps has fallen out of the public consciousness. I highly recommend you check it out. That chorus is magic. Absolute pinnacle of new jack swing. There's something about pop and R&B from, like, 1985-1995 that really resonates with me. Probably production stuff that I don't have the vocabulary to articulate.

So the bridge itself is in sort of an ABA form. The A section is traditional bridge material: change of perspective, different harmonic scheme, open-ended. The song is in major, but this A section is in the relative minor with an overall darker vibe. It could easily just be that and transition back to the chorus. Instead, it leads into the B section, a kickass sax solo by none other than Branford Marsalis. Man, I love shit like this. Then we get the A section again, which transitions into the chorus, as expected. At the end of the song we have Shanice singing the chorus with Branford on sax. Magical ending, with a nice callback to the bridge.

That's just the single edit. On the album version, Shanice adds a rap that leads into the sax solo (via a quotation of Debussy's Arabesque No. 1). So the full bridge is really ACBA, where A = sung bridge, C = rap, B = sax solo. And yeah, the rap is a little corny, but it adds to the overall tension of this middle section. Then that Debussy quotation (makes sense in the context of the rap lol) transitions the listener from the overall darkness of the bridge into that swanky sax solo, which is now in major.

Any formal novelties you guys are fond of?