A "perfect tensor" is defined on the [nLab](https://ncatlab.org/nlab/show/perfect+tensor) very abstractly as  "its tensor/hom-adjuncts $V^{\otimes k} \to V^{\otimes n - k}$ for $k \le n/2$ are isometries". The only example I'm aware of is the one used in the construction of the [HaPPY code](https://ncatlab.org/nlab/show/HaPPY+code).
What are other examples?