Any reason for not having:

fun <A> set(): Every<Set<A>, A> =
        object : Every<Set<A>, A> {
            override fun modify(source: Set<A>, map: (focus: A) -> A): Set<A> = buildSet {
                source.mapTo(this, map)
            }
                

            override fun <R> foldMap(M: Monoid<R>, source: Set<A>, map: (focus: A) -> R): R =
                source.foldMap(M, map)
        }

(and also maybe for Iterable...)?