The new smaller herb garden

When we first moved here there was a big open grass space to fill out the back and I went mad and had a huge herb garden. A triangle with each side about 10 metres long. With  a bay tree in the middle which started  out as not very tall but by the time we had to cut it down because it was blocking out all the light from the living room it was about 15 metres tall and nearly that round.
I grew all sorts of things that called themselves herbs but were really just weeds in disguise.
It took ages to keep it tidy at the start and then everything went wild and soon it was just a muddle.
Eventually we cut down the area to a oblong about 4 feet by 6 feet and still had things that were not really herbs and got too big.
Time to start again, in the new triangle made by moving the path - so it comes across to the new back door.

 A variegated Sage, Rosemary, Lovage, Chives, Fennel, Welsh onion,Common Thyme and my favourite Golden oregano/marjoram. None were bought as they have all grown from seed, cuttings or division from the old herb garden. I just need to keep everything under control and weed regularly until things have grown.
In pots I have my lovely Black Peppermint and a small Ginger Mint. Across the garden by the front fence, with room to spread is the Spearmint. Growing in the paths of one of the poly-tunnels are  Garlic Chives - they are not supposed to be there but seem indestructible. I also have two small Bay trees, one  in the garden and one in a pot. They were both self sown seedlings from the old Bay tree. And finally there is a Sweet Cecily in the flower garden and Lemon Balm on the edge of a shrub border.
There is a space for one more plant in the new herb garden, I can't decide what to put in.
What would you choose?
It must be useful.

Thanks to everyone for comments yesterday
Back tomorrow
Sue