Box isn't safe as such but it's not toxic either and buns leave it alone - well in my experience anyway and my buns will eat anything they can get their paws on - hence our borders are all fenced off. So you could think about some box bushes/hedging.
Bay trees are very safe and buns don't tend to eat these either.
Rosemary is only ever eaten as a last resort...e.g. winter! When nothing else is around. Lavender too, as mentioned above, is a bunny favourite but they don't go below the new growth usually so leave the woody stems - and this helps the lavender regenerate.
Nepeta all varieties is safe and buns tend to give it a wide berth, but if you have a cat or cats nearby you might end up with a few extra! (It's cat mint)
A large cardoon plant is tough - too tough for bunny to eat and safe - can make a nice feature in a garden. I grew mine from seed!
Willow, hazel - both can be used structurally in the garden. Willow sticks can be bought and just sunk into the ground to grow. A Mallow tree - has a huge thick stem when it grows and it lasts a couple of years as long as you don't get a big frost. My dad's mallow tree lasted about 5-6 years and was huge.
We have a large myrtle bush that our buns don't touch, I don't know how safe it is but as long as I keep it as a standard shape and trim off outgrowings below 2ft (bunny tiptoe height) they leave well alone and it is evergreen. Funnily enough they also leave the laurel bush alone and laurel is very toxic, it drops one or two leaves a year being evergreen and again we keep it trimmed to above 2ft but they don't touch the leaves on the lawn (thankfully). The leaves they DO eat are the spotted laurel but this isn't a true laurel anyway.
For herbs like thyme and marjoram etc you could make a wire cage to sit over them and then the buns can happily trim off what grows through the cage but the plant itself will be undamaged and you can lift off the cage to pick it if you want to use it.
However, every bun is different as to instinct of toxic plants and what they will and won't eat. It is always best to use caution in the garden and fence off or dig up anything you can't identify.