At some point in my work (which has nothing to do with set theoretics foundation) I need to consider the following axiom:
For any set $X$, any class $V$ with a surjective map $f : V \twoheadrightarrow X$ there exists a small subclass $V' \subset V$ such that the restriction of $f$ to $V'$ is already surjective.
(The general framework I'm working in is intuitionist mathematics with a notion of class, and small for a class mean in bijection with a set.)
It can be considered as a weak form of the axiom of choice, as the class valued axiom of choice would be about finding a $V'$ such that the restriction of $f$ is bijective (and in particular $V'$ would be small)
What I want to know is if this axiom appear somewhere in the literature. and especially does it have a name ? As it been studied or used ?