|Blue Flag Iris|
I call this unnamed yellow Iris the Wendy Iris because my friend Wendy gave them to me. If I don't know the actual name or cultivar of a plant, I often just give it a name. It's what used to be done back in the day, so why shouldn't I do the same?
If you want a lovely flower which comes in almost all colors of the rainbow, I'd tell you to go for an Iris. The best source for fantastic Iris collections is Gilbert H Wild and Sons. Every garden should at least have one Iris.