Looking to dye my hair a different color?

I'm really fair and pretty neutral toned with blue eyes and I'm a natural light blonde, but for the past year and a half or so I've been dying my hair a medium-dark auburn color with a lot more red than brown. It fades to sort of a coppery red color which I like too. I'm getting bored though and sort of feel like switching it up. Suggestions?

PS - It has to be a natural color because my employer doesn't allow me to dye my hair purple or green or anything.