Insouciant is a greyed lilac shimmer. In normal room light, the shimmer is rather subtle; in direct light, it flashes blue.
Decorous is a medium milk chocolate brown shimmer. Like Insouciant, its shimmer is on the shy side in indirect light but pops in stronger illumination.
Recherché is a creme, a deep dusty plummy creme.
Iconoclast is a black shimmer. This one was hard to capture on camera; in real life the shimmer flashes with a bit more color than the silvery blue that my lens chose to pick up on.
Insouciant is my favorite of these four; that soft purple shade looks like stepping out into one of the first welcoming warm days of spring feels. That said, I do see myself wearing the other three shades, too, so these are all winners for me. I used two coats of all but Iconoclast, which was one coat. Yep, I said one. Recherché was really close to being a one-coater as well.
If you'd like to see any of these compared to specific polishes, please leave a comment. If I've got the other polishes, I'll gladly do the comparisons.