I started making millet and quinoa porridge on Pidge's recommendation and I eat it myself now! Haven't worked out if it's cheaper than the Sainsbury's gf porridge or not, which I used to use.
We have buckwheat pancakes when I can get round to making them (usually at weekend).
You could also make hash browns, from normal potatoes or sweet potatoes. Or potato cakes from leftover mashed potato. Both good with baked beans and/or fried egg - depending on age of children and other food sensitivities of course.
Re oats etc., watch out because most rice krispie type cereals actually have barley malt added, and barley also contains a gluten-type protein. so does rye. So if you're avoiding gluten it would be best to cut those out too, at least at first. You can always try reintroducing them later and check for reactions.
Spod - if you're not avoiding yeast as well I love the sweet breakfast rolls made by ds (dietary specials) and also available in Sainsbury's. Sainsbury's also do some lovely syrup sponge puddings in their 'Free From' range but they can be hard to find.
I found an american recipe book for special diets in the library called the Child Friendly Food Allergy Cookbook. You have to convert some of the measurements but there are loads of ideas - mostly of the sweet or junk food variety but I guess those are the things most people miss?
Here's the list of the ones I have scanned in, if anyone wants copies. I haven't tried them all:
Brown sugar dough (for biscuits, sweet tarts etc.)
Cream puffs
Crunchy granola bars
Hot and yummy pockets
Kids' pizza-pizza
Low sugar baked rice pudding
Perfect pie crust
Pizza bites
Sweet potato cranberry muffins
Sweet potato hash browns
Vegan chip cookies
Wonder cake