also time signatures, most pop music is just 4x4 loops repeating again and again. Jazz is more free form and surprising
"Triplet-flow" in rap took the genre by storm after Migos and Future popularized it a while ago, and the initial appeal was the rhythmic novelty of it. (It obviously got stale after the novelty wore off.) Pop music in many of the big genres is in general, however, quite reticent to move away from perfectly riding a 4|4. Even using a 6|8 would be interesting.
There is a decent amount of pop music in 6/8. I always joke that it's like a hack to making a song better because 6/8 is rare enough that it makes the song sound interesting but common enough to not alienate the listener. It ends up sounding mostly like a hard swung 4/4 but then fills and some melodic lines are just a little bit more rhythmically spicy.
Some examples:
* The Doors - People are Strange
* T. Rex - Hot Love
* Fleetwood Mac - Don't Stop
* Depeche Mode - Personal Jesus
* Marilyn Manson - The Beautiful People
* Green Day - Longview
* Oasis - Lyla
* Blur - Parklife
* Living Things - Bom Bom Bom
* Britney Spears - Womanizer
* Goldfrapp - Strict Machine
* Feist - My Moon My Man
* Gotye - Heart's a Mess
* The Black Keys - Gold on the Ceiling
* Paul Kalkbrenner - The Grouch
I suspect that says more about me as a music listener than about the overall distribution of time signatures. I'm sure there's newer stuff using 6/8 too, but I don't listen to much pop music these days.