Many sauces aren’t considered okay for the low-fodmap diet, but thankfully, there are a select few that can add flavor to a meal. Personally, I would stick with spices to add flavor, because you can tweak them however you’d like, but I suppose that came from growing up with my mom the cook.
Also, for sauces, make sure to check ingredients. You don’t want to accidentally eat jelly sweetened with artificial sugars, or barbeque sauce with HFCS, do you?
basil, cilantro, coriander, parsley, rosemary, tarragon, thyme
allspice, cinnamon, cumin, five-spice, turmeric
mustard (check ingredients)
fish sauce, oyster sauce, soy sauce, Worcestershire sauce
all vinegars (except balsamic)
strawberry jelly or marmalade (check ingredients)
pesto (1/2 tbsp)
sweet and sour sauce (2 tbsp)
barbeque sauce (2 tbsp)
balsamic vinegar (1 tbsp)
ketchup (1 tbsp)
hummus, commercially prepared