What would be some good container planting combination ideas for the winter?

> 
> **A bit of extra info:** I live in Bristol, UK. And the containers would
>  be in a courtyard on the North-East side of the house, but in front of a very busy
>  road. On the other side of the road there is the river. 
> 
> 
> 

The amount of space available is reasonably big, and I have about a dozen of 15 litre pots.