I love to take multiple onion types (scallions, leeks, round onions, shallots, chives) and chop, then put with butter (I use a half of a frozen stick of butter) or evoo and s&p, in foil, and toss over the coals with whatever I'm grilling. You'd think that the round onions would overwhelm, but when they're all together like that, they blend to make a marvelous more complex flavor. This melange I use in almost anything. Add to stock (and obviously the aforementioned potatoes) for a soup of any kind. But just, as is, they are great tossed with pasta, into steamed rice, on a baked potato. There are only two of us, so when I get the coals going, I usually grill thinking in terms of more than one meal. I'll make whatever we're grilling for dinner, but always grill vegetables of some kind. Then I always put some chicken breasts on when the coals are dying back and we're eating. The veggies make for a great meal with just the starch for a meatless meal during the week that just is marvelous.
If your herb garden is booming as mine is, in the foil packet place a couple branches of thyme and one of sage. Leave them whole, for easy removal. The thyme leaves will come off into the onions, the sage will have flavored the mixture. Also, again, in the onion family, a couple of cloves of garlic.
As I said, you'd think that one of the alium family would overwhelm, but no, it doesn't, they just meld together and make a good addition to any other dish, and make super startch dishes.