[RichardA]

rocket, mitzuna and its various cousins, mixed salad leaf, baby spinach and pea leaves plus salad bowl as lettuce of choice.
R

[viettaclark]

I love my blood-veined sorrel. It has cropped well through the Winter, is simple to grow, is very pretty in the bed and on a plate and has a green lemony taste.

[Mazzie]

Beetroot tops, cant beat them in a salad 

[johnfh]

Land Cress(also called American Land Cress).  Strong cress flavour without the need for running water. Excellent in a mixed leaf salad if you like cress.  Mine has lasted right through the winter on a cut and come again basis. And is going strong again now.