OKRA ---------- No, no no! Many people put okra in their gumbo, but it is definitely not always an ingredient. The only ingredients that are part of any gumbo...or should be if it's true gumbo...are onion, celery, bell peppers and roux.
Gumbo recipes can be found on the sites All Recipes, the Food Network and Southern Food. Alternatively, the book 'The Little Gumbo Book' by Gwen McKee provides twenty seven different recipes for gumbo.