I have found that most grocery stores do carry low fodmap items that are gluten-free (GF), dairy-free, etc. Here is a list of foods that are high fodmap (avoid these), and a list of foods which are low fodmap that you can generally eat without problems. https://www.verywellhealth.com/foods-on-the-low-fodmap-diet-1944679
If you having a difficult time with this eating plan, I recommend that you ask your GI doctor for a referral to a registered dietician who can offer guidance. I am working with a dietician and she has helped explain the reason for the diet and how it helps. She even guided me to grocery stores in my area that carry an abundance of the low fodmap foods.
I have found there are some good books with recipes and suggestions for cooking. For example, you need to avoid garlic and onion (even garlic powder/salt and onion powder/salt). However, the dietician explained that you can use garlic infused olive oil which will add flavor to your foods without causing the digestive upsets.
You might check your local library to see what types of books they offer as well as your favorite bookstore.
How long ago did you start on the low fodmap diet, @moo1?