Would Cabal Stronghold count Snow-Covered Swamps?
Yes, the snow-covered lands do count as basic lands.


  205.4c Any land with the supertype “basic” is a basic land. Any land that doesn’t have this supertype is a nonbasic land, even if it has a
  basic land type.: Cards printed in sets prior to the Eighth Edition
  core set didn’t use the word “basic” to indicate a basic land. Cards
  from those sets with the following names are basic lands and have
  received errata in the Oracle card reference accordingly: Forest,
  Island, Mountain, Plains, Swamp, Snow-Covered Forest, Snow-Covered
  Island, Snow-Covered Mountain, Snow-Covered Plains, and Snow-Covered
  Swamp.