French dry bread are best. Avoid bread that are too soft as it will turn very soggy when egg mix is poured over. Apart from French loaf you can possibly use cinnamon rolls, croissants, Challah bread, bagels, even biscuits. Digestive biscuits, broken into chunks and spread on casserole with egg-milk-cream liquid to soak it up and crumble on top. If you are experimenting with biscuits, I recommend you to do the entire prep process just before baking. Don't make it ahead and in refrigerator overnight.