I love tree fungi. They tend to be overlooked because they are (mostly) not edible and not as flashy as, say, the Fly Agaric. But they are beautiful.
I don't have a picture, but Tinder Fungus (Fomes fomentarius) was and is used for making fire. It can also be used to make hats and even cloaks and as a hemostatic.
I don't know what species I have photographed, but I like how different they all are and how colourful.
Edit: I identified at least this one, I think, as Trametes versicolor