Which Wich is an international chain of sandwich and salad shops. You can choose to build your meal on a sandwich, salad or "Lettucewich". They have separate vegan and gluten-free menus on their website, so you can see what toppings are suitable. The signature Black Bean Patty (without cheese) and The Avocado are both vegan. Other suitable toppings include hummus, Dijon mustard, olive salad spread, peanut butter, grape jelly, cranberry sauce and all the veggies.
(can vary during public holidays)