This makes it a good finisher in a deck with many dragons that you want to attack, preventing you dying to the backswing, but it also helps in a defensive deck where you can sneak damage through while locking down threads so your dragons aren't required on defense
Use the power of the creature cards as they exist in your graveyard to determine whether they can be the targets of Reunion of the House
It can blow up in your face, but more often that not, you can sculpt your hand to achieve either the result you want or an acceptable loss
Once you get to 12+ counters, it can turn into a win condition, which is great upside to have
Most sources say that its actually Vanbrughs House, Vanbrugh in this case being Sir John Vanbrugh, an architect who designed a few very fancy estates in England in the early 18th century
You can preorder them now from your local game store, online retailers like Amazon, and elsewhere Magic products are sold.