Brussel tops are fab. I had the best ones once which re-grew at the top of my home-grown brussels after a very cold winter - they were so tender it felt cruel to eat them. (NB I didn't actually plant the brussels - I had just moved into the house the previous season!).
Also good are when you grow cabbages, cut them and leave the stalks, and little mini loose-leaf cabbages grow back. I have a bagful in the fridge for tonight, mostly Savoy.
Re: kale. The best kale in the universe is Russian Red Kale, we are lucky that a local place grows it, it is utterly delicious and much more tender and interesting than the dark knobbly Italian kind as well as the usual UK varieties. It has sort of oak-leaf-like leaves and goes dark green when cooked. We, for some reason, call it Red Roooshans in our house. Easy to grow if you have a bit of garden.