Tallullu - I rarely feed any solid veggies, except every once in awhile broccoli. I stick to leafy green veggies
I follow the guidelines of the House Rabbit Society
Romaine lettuce, parsley (both Italian and the bushy kind), dandelion greens, cilantro, mint, chicory, baby bok choy. I feed Kale in a blue moon because Jack loves it but gets that white sludge when he eats it.
The problem with the cabbage type veggies is it can cause gas and bloat in some bunnies. Which is painful, which then can lead to gi stasis (a slow down or stop of the intestinal tract.), and that is not good!
I know this is not only what the HRS cautions, but I have seen it myself with my bunnies. Rucy can't handle too much of that because she gets bloat and it gets serious.
Hope that helps!