you can test for future missing cards
example
Search “The Scourge” you will notice you have it 100% , card shows with no roots … now put filter on Path of Arthas set , here may be present or may be missing , and if it shows , it shows with roots .
Search “The Greybough” you will notice you have it 100% , card shows with no roots … now put filter on Darkmoon set , here may be present or may be missing , and if it shows , it shows with roots .
Search “Barak Kodobane” you will notice you have it 100% , card shows with no roots … now put filter on Barrens set , here may be present or may be missing , and if it shows , it shows with roots .
Search “Kalecgos” you will notice you have it 100% , card shows with no roots … now put filter on Rise of Shadows set , here may be present or may be missing , and if it shows , it shows with roots .
Search “Lady Liadrin” you will notice you have it 100% , card shows with no roots … now put filter on Outland set , here may be present or may be missing , and if it shows , it shows with roots .
Search “Madame Lazul” you will notice you have it 100% , card shows with no roots … now put filter on Rise of Shadows set , here may be present or may be missing , and if it shows , it shows with roots .
Search “Flik Skyshiv” you will notice you have it 100% , card shows with no roots … now put filter on Dragons set , here may be present or may be missing , and if it shows , it shows with roots .
etc etc
Now doing my test i noticed some i have and some i dont have , what i have remains in future , what i dont have is going to be missing.