By “open de Rham spaces” we mean moduli spaces of meromorphic connections over the trivial bundle on the projective line. Following the work of Boalch and later Bremer–Sage, I will explain how these spaces are defined, and hope to describe their relations to quiver varieties (where the underlying quiver possibly has “multiplicities”), hyperkaehler aspects, and extensions of some conjectures of Hausel–Letellier–Rodriguez-Villegas on the mixed Hodge theory of these and related moduli spaces.