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 Selenous Acid
Chemical formula: H2SeO3
Selenous Acid is Strongly Acidic
At concentration of 1 mM, it has a pH of 3.15
At concentration of 10 mM, it has a pH of 2.47
At concentration of 100 mM, it has a pH of 1.9