Knuckles_Bob_MarleybrocolliOkay that is like a tier 3 vegetable at best please try again.
Well, steamed broccoli makes for a very easy and healthy side which is enough for me to rank it pretty highly. Though I think I'd generally rank cauliflower above it.
Onions seems a bit too obvious, so I'd go with sweet potatoes or yams. Great by themselves, but can also makes a great additions to stir-fry, some types of curry, and really round-out dishes like this(very easy recipe).