This page will compile a list of all known runes within the Twilight Reign series, below are some facts about them:

There are 121 core Elven runes in the Land
There are also 505 lesser runes
They have a variety of meanings dependent upon shape
Simple angular shapes
Runes set in a circle are a singular word

List of Runes mentioned so far:
Xeliath (Meaning Heart)
Eache (Land)
Ehla (Light)
Merge
Union
Nyphal
Hit (Wind)