The Great Rift
The Great Rift separates the un-named region in the lower left hand corner of the Galaxy from the rest (it is more than 7ly from one side of the rift to the other - and hence unjumpable by hyperdrive/witchdrive engine). CaptSolo named the region as the Baying Wolf region, but it does not seem to have caught on.
There are almost 30 solar systems there.
Okti wrote 3 OXPs facilitating travel across the Great Rift: