While I think a large portion of Yara's fleet was destroyed...you still have all the slavers' ships.
Previews show the Unsullied ransacking Casterly Rock (Lannister home) which is on the other side of Westeros from Dragon Stone. So they have enough ships left for at least that. No way they walked across Westeros. I haven't seen anything on where the Dothraki are yet. And since the sand snakes/Dorne was my least favorite part of the show....no big loss for me there...actually Euron scored some points with me for killing 2 of the 3 daughters.
As far as houses being wiped out...While the Starks had the early lead, one house has passed them....the Baratheons...there's no one left...unless you count Cersei and Gendry...Cersei by marriage ( though I always think of her as a Lannister) and Gendry is a Barsteward. There may be a few more Barsteward children out there from Robert but Cersei hunted most of them down and had them killed. As far as I know only Gendry escaped her clutches.
And if you count the Baratheons/Lannisters as one family (since Joffrey, Myrcella and Tommen aren't really Baratheons) you only add Jamie and Tyrion to the list.