There are a few cards I keep wanting to build with but finding don't exist:
1) A "Reforge" spell. Maybe Fire or War? I want to "resurrect" dead equipment. It's too book intensive to play multiple copies of each equipment, since you can't always predict which one your opponent will destroy. It would be nice to have a spell that put them back together once they Dissolved, Corroded, or Exploded.
2) A level 2 "vanilla" Light creature like skeletal sentry or orc butcher.
3) A level 3 War school soldier. (This is my favorite ratio of cost:power:time in creatures, and it's brutal having to pay x2 for Knights of Westlock or Undead Knights.)
4) A level 3-4 flying (and elusive?) non-legendary demon to build a solo-ish Warlock in the vein of the Forcemaster. I want something that makes a good Blood Reaper while having a useful ability to avoid swarms and prey on a specific target. (I want an Invisible Stalker analog for my Warlock.)