I've used spelt, also einkorn and kamut flours - all ancient grains, I think. I usually use them half and half with modern wheat flour. Einkorn is my favourite, it doesn't rise much and has a soft texture, more like soda bread or scones. It is very nice with cheese, and with jam. Kamut is a golden flour, it gives a yellow colour to the bread. None of them rise as much as modern wheat flour, but they make nice bread.

I've been experimenting with using rye and barley flour as well. They make very dense loaves, so best mixed with lots of modern wheat flour. But they have a nice taste, so nice to have now and then. In England, we have a meal called "tea" which is mainly bread and different kinds of spreads (jam etc) and cake, and a nice cup of tea, so there's lots of opportunity to have different breads every day 😁