That leaves Kazuul in an awkward spot where it doesn't actually do what it says on the card very often
Thrun is good enough that even at four mana he has seen some Legacy play
They generate a powerful card and mana advantage that makes them staples in control lists for many competitive, 60-card formats and auto-includes in many Commander deck lists
Paying into X plus three mana always seemed like a hard sell to me when every mana counted, and drawing 1 card for 4 mana never seemed very good
Reaper King One of the original boogeymen of EDH before the format was renamed to Commander, the only thing that kept Reaper King from being an extremely toxic tribal build was the fact that there werent that many Scarecrows in Magic back then, and most that were in print were fairly mediocre
Theft is a key part of the blue/black Dimir decks (though it has spread to other colors) and is a very fun, if notorious, way to play Commander