Broadly, there are two different types of dairy-free muffins: those that contain eggs, and those that don't. Dairy-free muffins never contain milk, but depending on the diet an individual is following, eggs are an optional ingredient. In many cases, however, muffins that are dairy-free are egg-free as well, but it is important to verify this ahead of time. Otherwise, most standard muffin recipes can easily be modified to be dairy-free with a few simple substitutions, or there are many recipes to be found online for traditional favorites like blueberry, lemon poppy seed, and banana nut muffins that are designed as dairy-free alternatives.
In many recipes for dairy-free muffins, regular milk can just be substituted with an alternative like almond milk, soy milk, or rice milk. The type that is used is a question of personal preference. Almond milk is recommended fairly often because it is less sweet, but for people suffering from nut allergies, soy or rice milk are generally the only options. Soy milk has a slightly sweeter taste, but is also closest to regular milk. It may take some experimentation to find what works best in certain recipes, but they can usually be substituted with a one to one measurement.
Frequently, dairy-free muffins contain egg substitutes as well. In some instances, it is possible to just substitute cornstarch for eggs. In others, a vegan egg replacement can work also work well. In this manner, virtually any type of muffin recipe can be prepared for people with dairy allergies, lactose intolerance, or a simple preference to avoid any animal products. To make them a bit healthier, ingredients like oats, flax seed, and/or whole wheat flour rather than white flour may be used. As with most other muffin recipes, fresh or frozen fruits may be added if they are part of the recipe.
Chocolate dairy-free muffins exist as well. With these recipes, it is important to remember that pure cocoa powder or dairy free chocolate chips must be used, since many chocolate products contain milk as well. There are a number of other creative muffin recipes that are free of milk and/or eggs to be found in cookbooks and online, but be sure to check all the ingredients ahead of time, and make sure that they are actually free of milk and eggs. This is one of the reasons it is best to bake and cook items using whole, fresh ingredients as much as possible, because, that way, there is no question of the ingredients in the muffins.