Yeah, Crashbarrow + Graveyard is quite potent, especially if you can cheat out the Crashbarrow early with Garth. I don’t think it’s a coincidence that 3 of the decks in this tournament are [Necro]/Blood/x. I also had a bit of fortunate luck in how the draws lined up - Summon Skeletons on T2, Skeletal Archery on T3, and Graveyard on T4 were all exactly what I wanted, when I wanted them.
One counter strategy that gives me problems is just putting a lot of pressure on the board. Maxbanding Garth + Graveyard + Crashbarrow is a whole bunch of gold for stuff that I can’t or don’t want to patrol. I can usually only afford weak chumps like skeletons as patrollers, and maybe a Bone Collector if I’m lucky. If my opponent can get some solid early board pressure, it makes it hard to go that route without putting myself at substantial risk.