Theres also Brotherhood Regalia and Coerced to Kill and other effects that add assassin to their equipped/enchanted creatures types
(3/19/2021) If a spell on the stack has split second while you control Teferi, you can't suspend creature cards since split second stops you from casting them, even though suspending them is a special action
It can also be a miserable experience for those playing against it, as the strategy shut-offs fundamental mechanics
Its the same problem I have with Inexorable Tide, Assemble the Legion, and other 5+ mana enchantments
And a ton of commanders actually have enters-the-battlefield abilities (such as Godo, Bandit Warlord, Bladewing the Risen, Prime Speaker Zegana, or Venser, Shaper Savant)
It needed to be played at the right time, not to be a suicide, but Necropotence, even with its nothing goes to the graveyard and pay one life to draw a card was the pinnacle of deck building in Ice Age