Some numbers represented by symbols

Question

I am trying to find some numbers that are represented by symbols, such as π, e, i, φ. I couldn't find more. Can you guys help me?

(English is not my main language and it is for school project.)

Answer 1

A good source is here, but there are many more.

Answer 2

This one isn't on the Wikipedia list of mathematical constants, it's the Greek letter Tau.

$$\tau=2\pi$$

Answer 3

There are many more. $\zeta_n$ denotes $e^{2\pi i/n}$, an $n$th root of unity. $\gamma$ often denotes the Euler-Mascheroni constant. $G$ denotes Catalan's constant. In number theory, $\omega$ sometimes represents $(-1+\sqrt 3i)/2$, useful when we study the Euclidean domain $\mathbb Z[\omega]$.