Super Munchkin Underwater HQs, Part Redux!
 

Well, after discussing things with Andrew and James (the Warehouse 23 guy), it seems that the cards were the result of a printer error rather than ones meant for boosters, and so I can keep them. So once more...

Owing to a slight mixup at Warehouse 23, I recently came into possession of a whole bunch of the Underwater HQ card from the Warehouse 23 2010 Booster. I'm willing to trade them for cards from the rest of that set. That is -
Attic
Boo Fu
Bum Steer
Laser-Sighted
Pegasus Steed
Reload!
Stocking Stuffers
Tractor Beam
Trapped Chest

Cheers