This little website shows you the pH of various acids, bases, food products, bodily fluids, cleaners, and more!
Here's a random substance:
pH of Mesaconic Acid
Chemical formula: C5H6O4
Also known as: dimethylfumaric acid
Mesaconic Acid is Acidic
At concentration of 1 mM, it has a pH of 3.23
At concentration of 10 mM, it has a pH of 2.61
At concentration of 100 mM, it has a pH of 2.06