What to serve with jambalaya?

I agree with keeping the side vegetable-based with a rich meal like jambalaya. I have always liked these quick-pickled vegetables from an old Bon Appetit magazine, and it also could be a bit of a nod to giardiniera, especially if you use carrots and cauliflower in the mix: http://www.bonappetit.com/recipe/marinated-baby-vegetables. If you need a dessert to complete the theme, this is inspired by a trip to New Orleans: https://food52.com/recipes/38276-pimm-s-inspired-pavlova.

If you have hungry guests, make a menu like that for paella (same general sort of main).
Tapas, avoiding the shrimp & sausage in the main, greens or roasted red peppers.
Dessert, flan or fruit or both.
Drinks, wine, beer and/or lemonade.
http://www.sunset.com/food-wine/entertaining/paella-party-menu

Cornbread

With those kind of "all-in-one" meals, especially if they're somewhat rich....I think a nice, tangy garden salad or a crisp slaw is best for the side.