The special "Blank" units.

[Spartan-II]

In some maps I have played I have seen a high-templar and a battlecruiser but in the portrait it says "Blank". What editor do I use to get them?

[StealthyDeath]

Any other editor besides the original Staredit has them, like X-tra Editor. The templar one is Aldaris and the battlecruiser is either Gerald DuGalle or Arcturus Mengsk. Links to editors can be found in the Mapper and Modder Resource Thread.