Hmm fun fights for me:
T5, T9, T7(pre nerf and amusing post nerf), T10, Shiva ex, Titan(any), Levi Ex, Ultima Ex, Chrysalis, most of Wod

Hmmm I don't know if others ever notice this but for example for T9 elements... the movement for the elements is almost 1:1 match for T6 devour mechanic(and if you link it up a bit... could work with conflag/fireball from T5 to stand alone/group up except it's happening at the same time). People stack on tank while the marked person goes to stand on their own in a patch(hell even the LoS methods would work). They just built on it a bit more with the fire in/out. Thermionic beam is the same mechanic as missile in t8 where you need to group up. T7 fireballs prod at people to spread out like for streams in T9. So yes they do build up on the previous turns mechanics. It's usually just not as obvious and they do need to add something unique to them as well.

On top of that some of the mechanics are trying to teach the party itself to not tunnel vision. But to be honest if you look at any of the mechanic of any fight you are more than likely to find it was used in another fight just slightly different.