Here's a sample of what some English artists collect.
The above is the feces of a skunk. You can see it and nineteen other examples of feces at the National Poo Museum, which opened in March at the Isle of Wight Zoo in Sandown, England. It includes the feces of a pigeon, a meerkat, a lion a cowpat and others.
If you want to start your own 'museum', here's how. In your walks look for animal feces and take interesting ones home.
Then, dry it. Then put clear resin in a container like a fish bowl. You're finished when you put in the feces.