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 Hydrogen Selenide
Chemical formula: H2Se
Also known as: Hydroselenic acid, selane, selenium hydride
Hydrogen Selenide is Acidic
At concentration of 1 mM, it has a pH of 3.49
At concentration of 10 mM, it has a pH of 2.93
At concentration of 100 mM, it has a pH of 2.41