While technically not Z-stacks, the Epic by Madhouse I feel is one of the best stacked yoyos. They call their spinners “ta-ta’s”. This is an obnoxiously loud yoyo, just so you’re warned.
The Magic YoYo T9 and T10 as well as N9 are also available in “z-type stack” configurations as well as the hub stacked configurations.
The SuperStar and Mutant DNA(I have these as well) are compatible with the YYF Z-Stacks.
The Duncan MoMentuM also has Z-type stacks on it.
Some people say this stacked play is a novelty. I don’t completely agree. I will admit I don’t have the knowledge and the skill to really fully take advantage of what the potential play is with stacked yoyos. I do buy all sorts of stuff, and I like variety and options. I can always choose to NOT take advantage of a feature.