What is a facially valid warrant?

A warrant is a permission slip that enables police officers to temporarily suspend someone's 4th Amendment rights and violate their privacy for a specific purpose. In order to get such a permission slip, the police officer must have probable cause to believe that the warrant will likely reveal some specific evidence of a crime. Additionally, the warrant has to identify what area(s) the warrant applies to and what items are subject to seizure. For example, if a police officer suspects that a defendant has stolen a hippo from the local zoo, then it wouldn't make much sense for the warrant to let officers look through a defendant's sock drawers or under their bed. Instead, it'd likely identify large areas that could house such an animal, like the person's home, garage, RV, shed, etc.

Note that warrants involving electronic crimes can involve a wide array of seizure. For example, warrants being executed on individuals suspected of computer crimes usually involve the seizure of every electronic in the house that has storable memory, as well as every thumb drive or SD card. After all, any such place could have evidence on it of the computer crime.