I was wondering if there is a name for this 2-category which is like the 2-category of natural transformations, but does not actually require the 1-morphisms to be functors or the 2-morphisms to be natural transformations. That is
- the objects are categories
- the 1-morphisms between $\mathcal{C}$ and $\mathcal{D}$ are functions $Ob(\mathcal{C}) \to Ob(\mathcal{D})$
- the 2-morphisms between $F, G : \mathcal{C} \to \mathcal{D}$ are assignments $\eta_c$, for each object $c$ of $\mathcal{C}$, to a morphism $Fc \to Gc$
For my application I am typically considering the case where the objects are (category product) powers of a single category, rather than all categories, but I suspect it does not make much difference.