Wild Runes are a kind of naturally occuring 'pooled magic'. In ancient parts of the world where beings rarely travel mana can naturally pool and form these runes. There are people known as 'Runeseekers' who explore and search for these runes. They discover the runes and gain power from understanding them. This is similar to how geomancers gain power from understanding and controling the earth beneath them.
The Reflecting Pools are a famous place to gather Wild Runes as wild magic seems to pool there more quickly than in other parts of the world. It is commonly visited by magic users who wish to hone their craft in a welcoming environment.