From datamining we know that 12 new runes across 4 slots have been found for each class. I assume they are all in phase 2 (though that is not certain).
A few will probably be needed or very useful for the gnomeregan raid.
There are a lot of places they can be ‘discovered’ - STV, Arathi Highlands, Hillsbrad, Alterac Mountains, 1k needles, Dustwallow Marsh, Thousand Needles, Badlands and the lower level parts of Hinterlands, Feralas and Tanaris.
Is there a discovery discord (I know discoveries get quickly documented on wowhead - but as someone who likes to explore and wander - I’m more interested in helping with the ‘discovering’)