One of the best fermented foods I know of is kimchi (also kimchee), the food Koreans enjoy daily. They've spread the love for this food to other parts of the world. Recipes abound for the do-it-yourself version...or if you're time-strapped, pick up a good one, like Sunja brand, from your nearby healthfood store.
Why eat kimchi? For openers, it's a recognized digestive aid, high in fiber, active enzymes (much like yogurt and kombucha)). It gets better. For those of us who have allergies to dairy, it's a food completely free of dairy. For yeast sufferers who have to eliminate or limit vinegary foods, it's vinegar-free. From a health standpoint, it ranks high on foods to regularly enjoy.
Kimchi is also versatile. Eat it by itself (remember that even the medium spicy recipe isn't mild---at least by my tastebud settings); as a side dish, it perfectly complements meat, veggies, or scrambled eggs. Maybe you know of other wonderful combinations.
What's in kimchi? Veggies, many of them having their own healthful benefits---cabbage, onions, garlic, ginger, red peppers, carrots, leeks, sea salt.
Find kimchi in the cooler section of your healthfood store. The Sunja folks note on their label that kimchi contines to ferment, therefore, you'll want to store the jar in your fridge.